In single-celled organisms, materials are stored primarily in

• ribosomes

• mitochondria

• nuclei

• vacuoles

The human female reproductive cycle is regulated primarily by the

• white blood cells of the circulatory system

• muscle cells of the skeletal system

• enzymes of the digestive system

• hormones of the endocrine system

A photograph of a Siamese cat is shown here.

Siamese cats have dark fur on areas of the body that are cooler and light fur on parts of the body that are warmer. The color differences in this Siamese cat are most likely due to

• a decrease in glucose produced in areas with light fur

• more DNA molecules being produced in areas with light fur

• gene expression being influenced by the environment

• mutations in the genes for eye color

When deciding on new environmental policies and laws, which term is used to describe the comparison between benefits and costs of human activities?

• technology

• trade-off

• climate change

• industrialization

If the grass in the front yard of an abandoned house is not cut for several years, the yard may become overgrown with taller grasses, bushes, and shrubs. This is an example of the process of

• evolution

• homeostasis

• ecological succession

• direct harvesting

The northern snakehead is a type of Asian fish that eats smaller fish and is adapted to a freshwater habitat.

The presence of these fish in American waters is of concern because it might offer too much competition to native

• herbivores

• predators

• decomposers

• producers

In a food web, which type of organism receives energy from the other three types?

• producer

• carnivore

• decomposer

• herbivore

An ameba is a single-celled, heterotrophic organism. In order to meet its energy needs, it relies directly on the interaction of which cell structures?

• chloroplasts and the cell membrane

• the cell membrane and mitochondria

• nucleus and ribosomes

• vacuoles and the nucleus

Recently, oil from a wrecked tanker resulted in a disaster in ecosystems containing many unique species. The potential loss of these species could result in

• an increase in the variety of genetic material available

• a decrease in organisms available for scientific research

• an increase in the stability of the affected ecosystems

• a decrease in pollution affecting the land and water

Which process occurs at each link in a food chain?

• All the energy is stored in a newly made structure.

• Some energy is released into the environment as heat.

• Chemical energy is recycled.

• Atoms cycle among living organisms, producing energy.