A
B
C
D
100

When the carrying capacity for a species in a habitat is reached, the population of the species levels off. This slowing of the rate of growth is most likely due to

limited resources

100

Which characteristic is common to most types of cancer?

rapid and uncontrolled cell division

100

After a kidney transplant, special medications are taken. Otherwise, the patient’s immune system might react to the transplanted kidney by  

producing specialized proteins that would attack the kidney

100

In 2003, biologists encouraged nations to decrease the number of fi sh caught in order to help global fi sh populations recover. This seems to be helping some fi sh populations to increase. This increase in the size of some fi sh populations is a result of human

decisions that weighed the need for food with the need to maintain fi sh populations

200

On a hot day, dogs sweat through their paw pads and pant, which helps keep them cool. Both the sweating and panting are

a response to a stimulus

200

The human body fi ghts an infection when a pathogen is detected. As a result, the pathogen stimulates the production of

antibodies

200

Information that scientists are able to obtain from the fossil record includes

evidence about past environments and the history of life

200

During a woman’s menstrual cycle, ovulation occurs and an egg is released. This process is important because it allows for

 the egg to leave the ovary and be fertilized by a sperm

300

The formation of the many kinds of body cells that make up an embryo begins with

specific genes being activated

300

After digesting the nutrients from a meal high in carbohydrates, the body

releases insulin to return the blood sugar levels to normal

300

When an altered ecosystem is left undisturbed, the most likely result would be

a gradual shift toward a stable ecosystem

300

Many adults lack the ability to digest the milk sugar, lactose. Often, this is due to the insuffi cient production of the enzyme lactase, which breaks down lactose. This is not due to an allergy to milk. Milk allergies are different because they

result from an overreaction of the immune system to a harmless substance

400

A farmer stopped maintaining a fi eld that was once used to grow crops. Over time, the fi eld eventually became a forest. These changes best illustrate the process of

ecological succession

400

One reason energy must be constantly added to a stable ecosystem is because some energy is

lost at each feeding level

400

Information that scientists are able to obtain from the fossil record includes

evidence about past environments and the history of life

400

Experiments in mice show that a guardian gene that protects against type 1 diabetes can be altered by exposure to antibiotics during development. The exposure alters the gut bacteria, leading to a loss of the guardian gene’s protection. The loss of this protection most directly interferes with

homeostasis

500

The primary function of estrogen and progesterone is to

regulate reproductive cycles

500

Which statement best illustrates direct competition within a species?

Several squirrels eat acorns from the oak tree where they live.

500

Scientifi c claims should be questioned if

the experimental results cannot be repeated by other scientists

500

A new species of fl oating photosynthetic algae was accidently introduced into a pond ecosystem. It gradually replaced all the original algal species. A possible reason for the replacement could be that the new species

outcompeted the original algae populations for abiotic factors