Living Environment August 2022

Studying fossils provides evidence for evolution because fossils

• take a long time to form

• can show patterns of biological change over time

• always contain complete DNA sequences

• found in the same area are usually closely related to each other

Answer explanation

A fossil is the preserved remains of ancient organisms.

Fossils help researchers learn about plants and animals that existed long ago.

Which statement best describes the interactions between the structures found within a single celled organism?

• They allow the organism to maintain homeostasis

• They prevent homeostasis from damaging the cell.

• They must act independently of each other and prevent homeostasis.

• They carry out the same life process in order to maintain homeostasis

Answer explanation

Homeostasis is the ability of an organism to maintain a stable internal environment even when the external environment changes.

Sexually reproduced offspring have traits similar to their parents because they receive

• all of the proteins from each parent

• some of the proteins from both parents

• all of the genes present in both parents

• some of the genes present in each parent

Answer explanation

Sexual Reproduction is a method of reproduction that involves two parents to produce offspring that are genetically different from either parent.

Which row in the chart below correctly pairs a group of organisms with the type of nutrition they carry out?

• 1

• 2

• 3

• 4

Answer explanation

Autotroph - an organism that produces its own food. Also called Producers. Examples are Plants and Algae.

Heterotroph - an organism that cannot make its own food. Examples are consumers such as humans and animals.

The process that was most likely used to modify the plants’ trait and increase their natural rubber production was

• selective breeding of two similar plant varieties

• genetic recombination during sexual reproduction

• genetic engineering to alter a specific gene

• fertilizing the plants with key substances found in petroleum

Answer explanation

Genetic engineering allows scientists to move desired genes from one plant or animal into another. Genes can also be moved from an animal to a plant or vice versa. Another name for this is genetically modified organisms, or GMOs.

A response of a normally functioning immune system that can be harmful is

• being infected by the flu virus

• rejecting an organ transplant

• recognizing chemical signals

• fighting off a bacterial infection

Answer explanation

Acute rejection of an organ transplant happens when your body's immune system treats the new organ like a foreign object and attacks it. We treat this by reducing your immune system's response with medication.

Which molecules are normally found in single-celled organisms?

• organic molecules, only

• inorganic molecules, only

• both organic and inorganic molecules

• neither organic nor inorganic molecules

Answer explanation

All living things on Earth are composed of organic molecules. These molecules contain Carbon and Hydrogen.

Hammerhead sharks are unlike most other shark species. Nearly all shark species either lay eggs or give birth to live young after their eggs hatch internally. Hammerhead sharks form a placenta, a structure more commonly found in mammals, such as humans. One role of the placenta in the development of offspring is normally to

• produce blood cells

• provide milk

• produce gametes

• transfer nutrients

Answer explanation

The Placenta is the organ that enables nutrients and oxygen to pass from the mother's blood to the fetus and waste products to pass from the fetus to the mother's blood.

PCR, Polymerase Chain Reaction, is a method for carrying out DNA replication. In order to perform this technique, a scientist would need

• a DNA template, ATP, and 20 different amino acid subunits

• enzymes, several types of simple sugars, and starch molecule

• a DNA template, enzymes, and subunits with A, G, T, and C bases

• enzymes, specifi c receptor molecules, and several hormones

These strands are responsible for coding different proteins and are known as

• chromosomes

• mitochondria

• ribosomes

• chloroplasts