wayground logo

Free Printable Worksheets

Font size

S
M
L
XL
Worksheets

1st Half of Quarter 4 Last Chance Recovery

Total questions: 112

Worksheet time: 3hrs 1mins

Name
Class
Date
1.
An organism's appearance or other observable characteristics:
a)
phenotype
b)
recessive
c)
genotype
d)
dominant
2.
An organism's genetic make-up:
a)
phenotype
b)
recessive
c)
genotype
d)
dominant
3.
Natural selection can best be defined as the _____.
a)
survival of the biggest and strongest in a population
b)
survival and reproduction of those in the largest area
c)
elimination of the smallest organism by the biggest
d)
survival and reproduction of those that are best adapted
4.
Characteristics that allow a population to become better suited to its environment
a)
accommodation
b)
adaptation
c)
variation
d)
selection
5.
Which of the following is evidence for evolution?
a)
vestigial structures
b)
Embryology
c)
homologous structures
d)
all of these
6.
Some lizards have different size legs.  Lizards with longer legs are able to better access food. Over time, lizards with short legs became less common.
What is the successful adaptation?
a)
Lizards
b)
Long legs
c)
Food
d)
Leg sizes
7.
Mutations are a change in what?
a)
DNA
b)
tRNA
c)
genotype
d)
phenotype
8.
Why did the population of peppered moths in England change from the light variation to the dark variation after the Industrial Revolution? 
a)
The soot from industrial revolution caused the light peppered moth to fly away, and only the dark variation was left.
b)
The industrial revolution made the trees darker, which made white moths easier to catch by predators, so only the light moths were left.
c)
The industrial revolution made the trees darker, which made white moths easier to catch by predators, so only the dark moths were left.
d)
The soot from industrial revolution caused the light peppered moth to fly away, and only the light variation were left.
9.
A species of bird ate many types of seeds.  The individuals vary in beak size.  If a drought were to kill off the trees that produce small seeds and leave only large seeds, how would the population change?
a)
The birds with larger beaks were better at eating the large seeds than those with smaller beaks, so only the birds with larger beaks got enough food to survive, reproduce, and pass the trait of large beaks to the next generation.
b)
The birds with smaller beaks had to work harder than those with larger beaks to crack open the large seeds.  The more they used their beaks, the larger their beaks became, so they were able to get enough food to survive, reproduce, and pass the traits of large beaks to the next generation.
c)
The birds with smaller beaks grew their beaks so that they would be better able to eat the large seeds and get enough food to survive, reproduce, and pass the trait of larger beaks to the next generation.
d)
Beak size is random and will not be determined by the types of seeds available.
10.
Which of the following is REQUIRED for the process of natural selection to occur?
a)
Members of the same species must compete with one another.
b)
Members of different species must compete with one another.
c)
There must be a sudden environmental change.
d)
Traits must be inherited from one generation to the next.
11.
Why did the population of peppered moths in England change from light to dark after the Industrial Revolution?
a)
Light moths were easy to see against sooty trees and were eaten
b)
Light moths were killed by soot
c)
The birds that ate the dark moths were killed by soot
d)
Dark moths were produced by industrial processes
12.

What are the four groups of macromolecules?

a)

nucleic acids, proteins, carbohydrates, lipids

b)

nucleotides, amino acids, triglycerides, monosaccharides

c)

monomers, polymers, dimers, trimers

d)

glucose, fructose, sucrose, lactose

13.

All of these finches have different shaped beaks, they are an adaptation to gain access of

a)

Water

b)

Food

c)

Shelter

d)

Mates

14.
In natural selection, the selective agent is the
a)
humans
b)
mutations
c)
breeders
d)
environment
15.

Why has antibiotic resistance evolved in bacteria?

a)

Bacteria reproduce quickly

b)

Bacteria with a resistance to the antibiotic, passed that trait to offspring

c)

Bacteria that are resistant reproduce faster than non resistant strains

d)

Bacteria exposed to antibiotics develop a resistance to them

16.

Genetic drift is change in the allele frequency of a population due to...

a)

random chance

b)

natural selection

c)

non-random mating (sexual selection)

d)

artificial selection

17.

A(n)________ is a measure of how common a certain allele is in a population.

a)

Allele Frequency

b)

Gene Pool

c)

Genotypical Number

d)

Genetic Drift

18.
What is this an example of?
a)
diversity of species
b)
variation
c)
vestigial structures
d)
DNA studies
19.
A few deer wander out of their native woods into a completely new park where no deer had ever been before. They go on to create an entirely new population.
a)
Genetic Drift
b)
Natural Selection
c)
Non-random mating
d)
Mutation
20.
Five hundred years after the deer had established a flourishing population in the park, a few of them venture back to their original woods and have babies with the deer there.
a)
Genetic Drift
b)
Mutations
c)
Non-random mating
d)
Gene flow
21.
Wolves from the Arizona mesa were transferred to the Colorado Rockies after a forest fire destroyed their habitat. They quickly became part of the local pack and had offspring.
a)
Mutation
b)
Natural Selection
c)
Genetic Drift
d)
Gene Flow
22.
What does the image represent?
a)
Gene flow
b)
Gene drift
c)
Mutation
d)
Adaptation
23.
Survival of the Fittest and Evolution were proposed by what scientist?
a)
Charles Darwin
b)
Albert Einstein
c)
Steven Hawking
d)
Isaac Newton
24.
Gene Flow tends to ___________ genetic variation (diversity)
a)
Increase
b)
Decrease
c)
Stabilize
d)
Exaggerate 
25.

Evolution by chance, survival of the luckiest:

a)

genetic drift

b)

sexual selection

c)

fitness

d)

coevolution

26.

Charles Darwin said all that species share:

a)

a common ancestor

b)

the same DNA

c)

the same species

d)

a home

27.
Genetic recombination is the production of offspring - - - 
a)
with new combinations of genes
b)
with similar genes as their parent
c)
that are completely different from the parents
d)
that are super cute and irresistible
28.
Offspring LIKE parent = _________
Offspring DIFFERENT from parent = _________
a)
Parental : Recombinant
b)
Recombinant : Parental
c)
Linked : Unlinked
d)
Unlinked : Linked
29.

A scientist is studying two traits in a snail: body texture and whirls. Smooth body (S) is dominant to bumpy body (s), and whirl (W) is dominant to no whirl (w).

A SsWw and a ssww beetle mate and produce the number of offspring shown in the table. What % recombination is occurring here?

a)

33%

b)

25.6%

c)

29.6%

d)

70.4%

30.
Adenine bonds with ______________.
a)
Guanine
b)
Thymine
c)
Cytosine
d)
Adenine
31.
Guanine bonds with ______________.
a)
Adenine
b)
Guanine
c)
Cytosine
d)
Thymine
32.
Why is DNA important?
a)
it is very small and very complicated
b)
it's in everything
c)
it serves as the blueprint for traits of all living things
d)
because we eat it every day for energy
33.
Which 2 molecules forms the sides (backbone) of the DNA ladder?
a)
deoxyribose and adenine
b)
deoxyribose and a hydrogen bond
c)
sugar and the nucleus
d)
deoxyribose (sugar) and phosphate
34.
In a sample of DNA, 20 percent is Adenine. What are the percentages of the other bases?
a)
Thymine - 30 percent, Cytosine 25 percent, Guanine 25 percent
b)
Cytosine - 20 percent, Thymine - 30 percent, Guanine 25 percent
c)
Thymine - 20 percent, Cytosine 30 percent, Guanine 30 percent
d)
Thymine - 30 percent, Cytosine 30 percent, Guanine 20 percent
35.
DNA codes for...
a)
cholesterol
b)
proteins
c)
fatty acids
d)
a sandwich
36.
A change in the genetic code = ____
a)
trait
b)
genotype
c)
phenotype
d)
mutation
37.
DNA and RNA are macromolecules in the category of
a)
Proteins
b)
Lipids
c)
Nucleic Acids
d)
Carbohydrates
38.

Fossils are _________

a)

the most significant evidence of evolutionary relationships between species

b)

distinct and direct evidence of evolution

c)

a complete record of evolution

d)

all of the above

39.

Examples of homologous structures include

a)

the wings of a bat and a bird

b)

the wings of a bat and the limbs of a cat

c)

the limbs of a cat and the limbs of a tortoise

d)

none of the above

40.

An example of a vestigial structure is

a)

the forelimb of a whale

b)

the wings of an eagle

c)

the pelvic bone of a whale

d)

the tail bone of a monkey

41.

The strongest evidence for evolution from a common ancestor is

a)

similar DNA sequences

b)

similar body structures

c)

similar fossils

d)

all of the above

42.

The hands of different mammals are vestigial structures

a)

True

b)

False

43.

________ anatomy is the study of the similarities and differences in the structures of different species

a)

Human

b)

Comparative

c)

Relative

44.

The wings of a bat and birds are _________ structures

a)

vestigial

b)

homologous

c)

analogous

45.
The human appendix is a __________ structure that suggests that humans evolved from plant-eating ancestors.
a)
homologous
b)
embryonic
c)
essential
d)
vestigial
46.
The first organisms evolved on Earth around 4 billion years ago.  The fossil record indicates that the first organisms were which of the following?
a)
prokaryotes
b)
mitochondria
c)
plastids
d)
eukaryotes
47.
Which type of evidence is illustrated in this picture
a)
fossil evidence
b)
molecular
c)
anatomical
d)
embryological
48.
According to the law of superposition, the oldest fossils are found 
a)
At the top of the rock layers
b)
Near the bottom of the rock layers
c)
In the middle of the rock layers
d)
Somewhat near the surface
49.
Which of the following is NOT an example of a fossil?
a)
a petrified dinosaur bone
b)
a footprint captured in mud
c)
a seashell found on the beach
d)
an insect stuck in amber
50.
Miller and Urey experiment attempted to demonstrate
a)
how Earth first formed
b)
Whether DNA or RNA evolved first
c)
Whether organic molecules could have formed before life was present
d)
How the deepest part of Earth formed
51.
The structures shown are_________
a)
homologous
b)
heterologous
c)
analogous
d)
vestigial
52.

Scientists have found evidence that about 2.4 million years ago a gene regulating jaw muscles mutated and may have led to the more graceful human jaw we see today. The diagram below shows the skulls of 3 hominid species. Which statement below most closely explains the link between jaw size and hominid evolution?

a)

The jaws of hominids evolved to be smaller and less protruding over time as did the skull.

b)

The jaws of hominids evolved to be larger and more protruding over time.

c)

There appears to be no change in the jaws of hominids over time.

d)

The jaws of hominids changed over time due to a change in brain size

53.

Based on the illustration to the right, what do the similarities between human and chimpanzee hands and feet suggest about the different organisms?

a)

Chimpanzees and humans both have hands and feet adapted for walking upright, showing they have identical DNA.

b)

Chimpanzees and humans both have similar hands for grasping, proving they make and use complex tools.

c)

Humans and chimpanzees both developed five digits on their hands and feet, suggesting they have a common ancestor.

d)

Humans and chimpanzees both have thumbs, proving they eat similar foods like meat, nuts, and vegetation.

54.

How is the scientific theory of evolution supported by the comparison of the skulls and skeletons of modern humans and extinct hominids?

a)

By making the hip, spine, and skull comparisons, the age of different hominid specimens can be determined.

b)

Comparison of skull and skeletons provides evidence that humans and different hominid species interacted.

c)

Similarity in skull shapes, hands, and hips between extinct hominids and humans supports a common ancestry.

d)

Skull and skeleton comparisons can explain why hominids were inferior and became extinct while humans evolved.

55.

The ability to walk upright on two legs is called:

a)

bipedalism

b)

quadropedalism

c)

bicyclepedalism

d)

tripedalism

56.
Which of the following correctly summarizes the physical changes that early humans went through over the past million years or so?
a)
Brain size increased as jaw size decreased
b)
Brain size decreased as jaw size increased
c)
Bipedalism increased as use of tools increased
d)
Bipedalism decreased as the use of tools increased
57.

The illustration below shows four lobes of the human brain.


What lobe is designated by label 2?

a)

temporal

b)

parietal

c)

occipital

d)

frontal

58.

Which lobe of the brain is designated by number 4?

a)

Occipital Lobe

b)

Parietal Lobe

c)

Frontal Lobe

d)

Temporal Lobe

59.

Modern humans and their closest relatives belong to the same family. Members of this family are called:

a)

hominids

b)

primates

c)

homo sapiens

d)

Lucy

60.

What continent did humans evolve from?

a)

the Americas

b)

Asia

c)

Africa

d)

many places all at once

61.

Which is the oldest of these four species?

a)

Australopithecus

b)

Tool-making hominids

c)

Homo Neanderthalensis

d)

Homo Sapiens

62.
Which question were the scientists trying to answer with this experiment?
a)
Where do cells come from?
b)
How did prokaryotes form cell membranes?
c)
How are biomolecules formed?
d)
What gave rise to the Eukaryotic cell?
63.
The apparatus in the experiment was used to mimic what?
a)
Proteins
b)
Present Earth conditions
c)
Early Earth conditions
d)
Nucleic acids (DNA/RNA)
64.
This experiment was conducted by the scientists:
a)
Stanley Miller and Harold Urey
b)
Harold Urey and Albert Einstein
c)
Louis Pasteur and Francesco Redi
d)
James Watson and Francis Crick
65.
Miller/Urey and other scientists have shown that:
a)
 Life on early Earth required material from space
b)
Cells survived in the primitive atmosphere
c)
Amino acids could be produced from inorganic molecules 
d)
Simple cells can be produced in a laboratory
66.
The idea that Earth's early oceans had organic molecules that became the first life is called the...
a)
Primordial soup hypothesis
b)
Bubble hypothesis
c)
Miller-Urey Experiment
d)
Radioactive dating theory
67.
Which of the following was probably not present in the atmosphere of the primitive Earth? 
a)
methane
b)
oxygen
c)
water
d)
carbon dioxide
68.
The smallest unit which can be considered life is called __________. 
a)
 a prokaryote
b)
a LUCA
c)
a cell
d)
a phospholipid
69.
Which 'building block of life' was NOT made in the Miller Urey experiment?
a)
amino acids
b)
nucleic acids
c)
sugars
d)
lipids
70.
Which of the following describes what the first life form resembled?
a)
Eukaryotes
b)
Plants
c)
Bacteria
d)
Fungi
71.
Which of the following supports the hypothesis of an “RNA world” on early Earth?
a)
Some RNA molecules are important catalysts in modern cells.
b)
The oldest known fossils contain trace amounts of RNA.
c)
Single-stranded RNA molecules are linear and do not form three-dimensional shapes.
d)
RNA is the primary genetic material of many viruses.  
72.
Which of these are the ingredients NEEDED for life to form?
a)
organic macromolecules
b)
atoms
c)
methane 
d)
inorganic molecules
73.

Which group is not represented in the food web?

a)

producers

b)

primary consumers

c)

secondary consumers

d)

decomposers

74.

What do the arrows in the food chain indicate about the flow of energy in an ecosystem?

a)

Energy is continuously recycled by the organisms in an ecosystem.

b)

Energy flows in one direction in an ecosystem, from producers to consumers.

c)

More of the available energy in an ecosystem is given to large animals than to small animals.

d)

Organisms at the end of the food chain receive more energy than those at the beginning.

75.

In this energy pyramid, which organism would most likely be in level 2?

a)

bird

b)

fox

c)

caterpillar

d)

tree

76.

Which one of the following is true of grass in an ecosystem?

a)

It converts oxygen to glucose.

b)

It produces carbon dioxide from oxygen and water.

c)

It produces glucose from carbon dioxide and water.

d)

It converts water to energy.

77.

How would the removal of earthworms from the food chain affect the other organisms?

a)

The number of bass will increase.

b)

The number of crayfish will decrease.

c)

The crayfish will get their energy directly from the sun.

d)

The number of bass and ospreys (bird) will increase.

78.

Interactions in an ecosystem result from the transfer of matter and energy from producers to consumers and eventually decomposers. What are the forms of energy transfer from numbers 1 through 4?

a)

Chemical energy to chemical energy

b)

Light energy to chemical energy

c)

Chemical energy to heat energy

d)

Heat energy to mechanical energy

79.

The diagram shows part of an aquatic food web for a stable lake ecosystem in Connecticut. What is the source of energy for the algae?

a)

waves

b)

sunlight

c)

bacteria

d)

rotifers, water fleas and tadpoles

80.

Suppose that a new predator of the rabbit migrated to this ecosystem. What is the most likely initial effect on the other organisms?

a)

More competition among the mice for food

b)

More competition among the hawks for food

c)

Less competition among snakes for food

d)

Less grass available for food

81.

For the food chain shown, which of the following changes would have the most severe consequences?

a)

a drastic decrease in rainfall, causing a drought

b)

the poaching of predatory hawks by game hunters

c)

the introduction of a second predator that eats field mice

d)

a parasitic infestation that reduces the cricket population

82.

The diagram provided shows a marine food chain. In this food chain, the zooplankton are

a)

primary producers.

b)

primary consumers.

c)

secondary consumers.

d)

tertiary consumers.

83.

The picture shows an energy pyramid. What will most likely happen to the foxes and the wolves if the rabbits are removed?

a)

The foxes will eat more wolves.

b)

The foxes will eat fewer wolves.

c)

There will be more foxes and wolves.

d)

There will be fewer foxes and wolves.

84.

A student examines the information in the table. The student concludes that Organism W should be placed at the base of the food web to represent the feeding relationships in the marine ecosystem. However, the student later learns that Organism W's cells do not contain chloroplasts. Based on the new information, which conclusion would be appropriate?

a)

Another organism in the marine ecosystem is a producer.

b)

Organism W is a secondary consumer in the marine ecosystem.

c)

The role of Organism T in the marine ecosystem changes during its life.

d)

This marine ecosystem does not have any producers.

85.

Which of these organisms would most likely be found at the top of an energy pyramid?

a)

clams

b)

sardines

c)

sharks

d)

kelp (seaweed)

86.

The picture shows the energy flow through a meadow community. Which of the following would most likely occur to the populations within the community of organisms immediately after a wildfire burns the environment?

a)

Hawks would increase and foxes would increase.

b)

Hawks would decrease and foxes would increase.

c)

Meadow plants would increase and rabbits would decrease.

d)

Meadow plants would decrease and rabbits would decrease.

87.

Which of these organisms would most likely be found at the bottom of a biomass pyramid?

a)

giant squids

b)

sand sharks

c)

sea cucumbers

d)

green algae

88.
Which of the following would be the most likely effect, if there were a sudden increase in the cricket population?
a)
There would be a decrease in the small bird population.
b)
There would be a decrease in the grass/flowers population.
c)
There would be a decrease in the mice population.
d)
There would be an increase in the grass/flowers population.
89.
What does a Primary Consumer eat?
a)
Tertiary Consumers
b)
Secondary Consumers
c)
Producers
90.
An organism that lives by breaking apart dead organic matter into simpler parts is...
a)
scavenger
b)
consumer
c)
decomposer
d)
carnivore
91.
What does a food web represent?
a)
All connections of energy flow throughout all organisms in a ecosystem.
b)
The specific ways that mutualism is carried out.
c)
A single pathway or energy flow between organisms. 
d)
How carnivores get their food. 
92.
Which organism receives the least amount of energy from the producer?
a)
Owl
b)
Grasshopper
c)
Lilypad
d)
Mouse
93.
Which organisms from the Food Web is consuming the Insects?
a)
Lynx, Hare
b)
Shrew, Red fox
c)
Lynx, Red Fox
d)
Hawk, Shrew
94.
If the sun provides all energy in the Energy Pyramid, and the energy decreases by a division of 10 as you travel up the pyramid, how much energy does the Tertiary Consumer have?  
a)
100%
b)
10,000%
c)
10%
d)
.1%
95.
What is the process in plants that produce food for the plants and oxygen.
a)
photosnthesis
b)
I don't know
c)
Photosynthesis
d)
growing
96.
When a population grows past the ecosystem's carrying capacity, what happens to the population?
a)
Continues to grow
b)
The population starts to die off to return to carrying capcity
c)
The population will go extinct due to lack of resources
d)
The population grows then finds a new carrying capacity
97.
If there is more food than usual in an ecosystem, then...
a)
Populations will stay the same
b)
Populations will decrease
c)
Populations will increase
98.
What is it called when an organism leaves an area or population?
a)
immigration
b)
limiting factor
c)
emigration
d)
death rate
99.
Space, food, water, weather conditions, disease, and climate/weather conditions  can be examples of what?
a)
biotic factors
b)
limiting factors
c)
abiotic factors
d)
death rate
100.
Which is NOT a process of the water cycle?
a)
precipitation
b)
freezing
c)
transpiration
d)
evaporation
101.
The process of plants losing water through their leaves is called ____.
a)
condensation
b)
evaporation
c)
transpiration
d)
exhaling
102.
What is the only process that removes carbon from the atmosphere?
a)
combustion
b)
cellular respiration
c)
photosynthesis
d)
decomposition
103.

A biologist compares how different ecosystems undergo succession. She divides the series of events happening during succession into different stages. What feature below is found only in secondary succession but not in primary succession?

a)

the lack of pioneer species in the second stage

b)

the presence of pioneer species in the final stage

c)

the presence of trees and large plants in the final stage

d)

the presence of soil in the first stage

104.

Scientists that study the effects of global warming predict that a change in Earth's average temperature of even a few degrees will have dramatic effects. One consequence of global warming is the melting of the polar ice caps, which will in turn affect polar bear that use sea ice as a platform for hunting seals. What will most likely happen to the population of polar bears as a result of global warming?

a)

It will increase as polar bears adapt to other habitats.

b)

It will increase because polar bears will have fewer predators.

c)

It will decrease as the habitat suitable for polar bears decreases.

d)

It will decrease because polar bears will become easier to hunt.

105.

As forested areas are cut down, habitats are often permanently changed to agriculture or other land use. How does the conversion of natural forest to human land uses affect an ecosystem?

a)

There will be a decrease in biodiversity in the ecosystem.

b)

There will be an increase in animal populations in the ecosystem.

c)

There will be less space to plant crops and build houses in the ecosystem.

d)

There will be more nutrients in the ecosystem's soil after the forests are cut down.

106.

In the 1930s, the Red Imported Fire Ant was accidentally introduced into the United States. This species is native to South America, but has thrived in the United States because of a lack of natural enemies here. Which of the following best explains how the Red Imported Fire Ant has affected native ant species in the U.S. that do have predators?

a)

Native ant species preyed on the Red Imported Fire Ant and increased in population.

b)

Native ant species interbred with the Red Imported Fire Ant, creating new ant species.

c)

The Red Imported Fire Ant caused native ant species to become more susceptible to predators.

d)

The Red Imported Fire Ant caused a decline in native ant species by competing for their resources.

107.

Why are there so few aquatic plants and phytoplankton that live at the bottom zones in the ocean?

a)

The ocean floor contains many decomposers.

b)

Most sunlight is absorbed before reaching these levels.

c)

Water is a limiting factor.

d)

The temperature in these zones is extremely low.

108.

The pH of the water in several lakes in Norway and Sweden had decreased to below 5.0 due to an increase in acid rain. Which of the following is most likely to happen in these lakes?

a)

the decline of several fish populations.

b)

an increase in the amount of primary producers

c)

an increase in numbers of fish

d)

increased predator-prey relationships

109.

Salt water is an abundant resource but unusable for irrigation and drinking. As demands on freshwater sources increase, the use of desalination processes to remove salt from ocean water is increasing. A concern of desalinating water is the large amounts of recovered salts that are returned to the ocean. Which of the following describes the most likely impact of desalination on the surrounding ocean environment?

a)

Methane gas would pollute the ocean environment as shoreline organisms begin to die and decay.

b)

Alteration in ocean salt levels would cause loss of species biodiversity and unbalanced populations in marine food webs.

c)

Nonrenewable resources in the ocean environment would become depleted and upset the ecosystem's balance.

d)

Increased levels of salts and minerals in the ocean would result in overpopulation of marine bivalves due to strengthened shells.

110.

Which of the following is matched correctly?

a)

hurriances- density dependent facto, abiotic

b)

hurricanes- density dependent factor, biotic

c)

hurricanes- density independent factor, abiotic

d)

hurricanes- density independent factor, biotic

111.

Every year, monarch butterflies from Canada and the United States, spend the winter in central Mexico. The dry and mild climate in Mexico allows the monarch butterflies to survive the winter. One winter, a week of storms caused freezing temperatures and 43 cm of snow in Mexico. What was the most likely impact of these storms on the monarch butterflies?

a)

Monarch butterflies died in large numbers.

b)

Monarch butterflies immediately migrated back to the United States.

c)

Monarch butterflies did not migrate from Canada and the Untied States the next year.

d)

Monarch butterflies evolved several new adaptations to survive the winter in Mexico.

112.

Five hundred years after the deer had established a flourishing population in the park, a few of them venture back to their original woods and have babies with the deer there.

a)

Genetic Drift

b)

Mutations

c)

Non-random mating

d)

Gene flow