1. Scientists studied a rattlesnake population from 1972 until 2002. No snakes moved into or out of the population during this time. The population numbers are shown on this graph. Which of these most likely happended between 1992 and 2002?

O   a. The birth rate was greater than the death rate.
O   b. The birth rate was less than the death rate.
O   c. The death rate was equal to the birth rate.
O   d. The death rate and birth rate remained constant.

O   a. a magnifying glass to view the chloroplasts
O   b. a magnifying glass to view the mitochondria
O   c. a microscope to view the chloroplasts
O   d. a microscope to view the mitochondria

3. A scientist performed an experiment to determine the best level of light intensity for photosynthesis in an aquatic plant. He varied the light intensity and measured the amount of a gas produced by the plant at each level of light intensity.

Which of these is the dependent variable in this experiment?

O   a. type of plant
O   b. light intensity
O   c. amount of oxygen produced
O   d. amount of carbon dioxide produced

4. Hody performed an experiment on four equal-sized tomato plants. She placed each tomato plant in a separate container. Jody gave each plant the same amount of light and nutrients, different amounts of water, and frequently measured the amount of oxygen produced by each tomato plant.

Which of these is the hypothesis Jody was most likely studying in this experiment?

O   a. If the amoount of light is increased, then the rate of photosynthesis will increase.
O   b. If the amount of nutrients is increased, then the rate of cellular respiration will increase.
O   c. If the amount of water is increased, then the rate of photosynthesis will increase.
O   d. If the amount of water is increased, then the rate of cellular respiration will increase.

5. This picture shows Essie performing a laboratory experiment. Which of these should Essie do to make her experiment safer?

O   a. leave the laboratory when the hot plate is on
O   b. use bare hands to remove the test tubes
O   c. wear safety goggles during the experiment
O   d. place corks in the test tubes to prevent them from boiling over

6. John has been studying a species of butterfly that can live in only one type of habitat. These graphs show how the size of the butterfly population and the amount of its habitat have changed during the last century. In 2001 ecologists began restoring areas of the butterfly's habitat that had been converted to farmland during the last century. If the trend of restoring the butterfly's habitat continues, which of these will most likely happen to the butterfly's population?

O   a. the butterfly population will become extinct
O   b. the butterfly population will increase in size
O   c. the butterfly population will become a new species
O   d. the butterfly population will adapt to a different type of habitat

7. Doctors are studying the effectiveness of a medicine when given at ceratin doses. This medicine increases the sensitivity of neurons to stimuli. Above which dose does the medicine immediately begin to decrease the activity of the neurons?

O   a. 0.5 mg/dose
O   b. 1.0 mg/dose
O   c. 2.5 mg/dose
O   d. 3.0 mg/dose

8. A biologist is studying a species of crab. He hypothesized that if a crab has larger pincer claws, then it will have greater reproductive success. He placed 50 crabs with small pincers and 50 crabs with large pincers together in an isolated area that closely resembled their natural environment. He ovserved several generations of the crabs over the next ten years.

If his hypothesis is correct, which of these results would he most likely observe?

O   a. the percent of crabs with large pincers would increase
O   b. the percent of crabs with small pincers would increase
O   c. the DNA in crabs with small pincers would mutate in order to produce larger pincers
O   d. crabs born with small pincers would develop larger pincers and pass this trait to their offspring