Which of these is necessary for natural selection to occur?

Rabbits that live in warm climates have larger ears than rabbits that live in cold climates. Larger ears allow rabbits to cool themselves by releasing body heat. Which term describes this characteristic?

Students collected leaves from four maple trees. They measured the length and width of each leaf. Then they calculated the average values for each tree. The data are shown in the table below.

According to the data, which tree has a selective advantage in capturing sunlight?

The mole rat is an animal that avoids predators by living underground. Its long claws and teeth allow it to dig deep holes. Scientists believe the ancestors of the mole rat lived above ground and had shorter claws and teeth.

Which of these processes resulted in the long claws and teeth found in the modern mole rat?

Use the information below to answer the following.

The largest flower in the world, called a rafflesia, is three feet wide and weighs up to 36 pounds. The rafflesia has no roots, stems, or leaves. It lives on and takes nourishment from a vine called tetrastigma. The rafflesia harms the vine.

The seeds of the rafflesia are dispersed in an unusual way. Plantain squirrels and tree shrews eat parts of the rafflesia plant. Scientists observe that when the animals chew the rafflesia, seeds get caught in their teeth. The animals will then chew on tetrastigma vines, leaving the seeds where they can germinate.

Rafflesia flowers produce the smell of rotting flesh. This smell attracts flies. When the flies land on the flowers, the pollen attaches to them. The flies then transport the pollen to other flowers.

Producing a smell to attract flies is an example of

Use the technical passage Elephants Don't Need Email to answer the following.

Elephants travel long distances in search of food. Using infrasound, family members traveling separately can communicate with each other.

The ability of the elephants to communicate over long distances probably developed

Use the technical passage Shortage of Honeybees to answer the following.

South American honeybees are resistant to the mites. Scientists believe that the North American honeybees may also become resistant to the mites in another ten years.

Which of these processes will cause the honeybee population to become resistant to the mites?

Which of these will most likely result in variation within a species?

Loggerhead turtles in the Atlantic Ocean return to lay their eggs on the same beaches where they hatched. Scientists have observed that the turtles have a “compass sense.” This sense allows them to use Earth's magnetic field to find their way back to the beaches where they were hatched.

Which of these terms best describes the turtle's ability to use Earth's magnetic field?

A species of birds lives on an island. The thickness of the birds' beaks varies within the population. The birds feed mainly on seeds from plants. Birds with thinner beaks can eat only small seeds. Only birds with thicker beaks can crush and eat large seeds.

There are many small seeds during years with more rain. During dry years, there are very few small seeds and many large seeds. The large seeds are harder to crush than small seeds.

The graph below shows the average beak thickness in the bird population from 1979 to 1985: 1980 and 1982 were dry years; 1984 was a wet year; 1979, 1981, 1983, and 1985 received normal rainfall.

• Explain why the average beak thickness changed between wet and dry years.
• Explain how beak thickness would have changed during the next ten years, 1986 to 1996, if these years were wet years.
• Name the process that led to this change.

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Researchers are studying slider turtles. Slider turtles hatch on the beach. The researchers discovered that larger baby turtles were more likely to survive than smaller baby turtles. They hypothesized that the larger turtles could move more quickly toward the water than the smaller turtles, reducing their exposure to predators.

The survival advantage for the larger baby turtles is a result of

The figure below shows the skeletal structure of a seal's flipper and a monkey's arm.

The skeletal structures of the flipper and the arm are similar, even though they have different functions. Seals use their flippers for swimming, while monkeys use their arms primarily for grasping and lifting.

The seal's flipper and the monkey's arm differ in appearance. This difference is the result of

The ears of foxes help to regulate body heat. The fennec fox lives in the North African desert and has large ears that release body heat. The Arctic fox lives in cold climates and has small ears that conserve body heat.

Which of these processes led to the development of different ear sizes in foxes?

Students conducted an experiment to test the effect of antibiotics on bacteria. They placed bacteria in a petri dish that contained agar treated with an antibiotic. Only one of the bacterial colonies survived.

Which of these statements best explains why only one colony survived?

Amphibians were the first vertebrates to live on land. The ancestors of amphibians were probably lobe-finned fish. The diagram below shows this development of amphibians over time.

Which of these terms best describes how amphibians could have developed from lobe-finned fish?

Marine and land iguanas are two different species that inhabit the Galapagos Islands. Some scientists believe that both species diverged from a common ancestor. Marine iguanas eat algae. Land iguanas feed on cacti. Algae are more abundant in the ocean than cacti are on the islands. Both species lay their eggs in the sand.

Rats, cats, and goats have recently been introduced to the islands. Rats often feed on iguana eggs, cats eat baby iguanas, and goats eat cacti.

Explain how the two species of iguanas could have developed from a common ancestor. In your response, be sure to

• name the process that explains how marine and land iguanas developed from a common ancestor
• describe the steps involved in this process
• explain how the introduction of rats, cats, and goats might affect both iguana species

Write your answer in your Answer Book.

Use the information and the figure below to answer the following question.

Male fiddler crabs attract females by quickly waving their large front claw. If a claw is lost in a fight or accident, they quickly grow a hollow claw of equal length. Because the new claw is lighter, they can wave it faster. A male fiddler crab is shown below.

The male fiddler crab’s new claw can be described as

Use the information and the figure below to answer the following question.

Male fiddler crabs attract females by quickly waving their large front claw. If a claw is lost in a fight or accident, they quickly grow a hollow claw of equal length. Because the new claw is lighter, they can wave it faster. A male fiddler crab is shown below.

The new claw probably helps the male fiddler crab to

Use the information below to answer Numbers 11 and 12.

Use the information below to answer the following item.

An insecticide is a chemical that kills insects. Most insects are killed the first time they are exposed to an insecticide. However, some insects carry a gene that enables them to survive their first exposure to an insecticide. When these surviving insects reproduce, this gene may be inherited by their offspring. The number of insecticide-resistant insects usually increases over time because increasing numbers of offspring with this gene are able to survive and reproduce.

Which process enables increasing numbers of insects to survive their initial exposure to an insecticide?

Some farmers in India grow a species of rice. In 1970 a virus destroyed most of these rice plants. Some of the rice plants survived the virus. These plants grew and produced a new generation of plants that were not affected by the virus.

• The population of rice plants changed as a result of the virus. Name and explain the process that caused this change in the population of rice plants.
• What were some differences between the plants that survived and the plants that died?
• Describe the most likely reason the surviving plants were able to grow and continue to reproduce.

Write your answer in your Answer Book.

Use the information and the drawing below to answer Numbers 19 through 21.

Use the information and the drawing below to answer the following item.

The desert climate is caused by geographic conditions such as location, high atmospheric pressure, and proximity of mountain ranges. Average desert rainfall amounts are usually less than 50 cm per year. Soil in deserts is coarse, sandy, and rocky. Desert plants and animals have specialized characteristics that help them survive in the harsh environment. An example is the Saguaro cactus. The Saguaro has a shallow root system with a main taproot and other roots that radiate out and collect surface water. The trunk of the Saguaro has the ability to expand while storing water. The sweet-nectar flowers of the Saguaro attract white-winged doves, bats, and other animals. These animals feed on the nectar. They are necessary for cross-pollination. Cross-pollination occurs when the pollen of a flower is carried to a flower on another plant. The illustration below shows the Saguaro cactus.

Which advantage is the most likely result of cross-pollination to Saguaro cacti?

Use the information and the drawing below to answer the following item.

The desert climate is caused by geographic conditions such as location, high atmospheric pressure, and proximity of mountain ranges. Average desert rainfall amounts are usually less than 50 cm per year. Soil in deserts is coarse, sandy, and rocky. Desert plants and animals have specialized characteristics that help them survive in the harsh environment. An example is the Saguaro cactus. The Saguaro has a shallow root system with a main taproot and other roots that radiate out and collect surface water. The trunk of the Saguaro has the ability to expand while storing water. The sweet-nectar flowers of the Saguaro attract white-winged doves, bats, and other animals. These animals feed on the nectar. They are necessary for cross-pollination. Cross-pollination occurs when the pollen of a flower is carried to a flower on another plant. The illustration below shows the Saguaro cactus.

Which of these adaptations is most important for the Saguaro to survive long periods of drought?

Crops must be able to compete with weeds in order to be successful. Certain crops have been genetically modified to be resistant to specific herbicides. In areas where these crops are grown, the herbicides can be sprayed to kill weeds without damaging the crops. However, weeds in these areas have begun to show resistance to the herbicides.

The environmental pressure most likely responsible for an increase in the number of resistant weeds is

Use the information below to answer Numbers 70 and 71.

Use the information below to answer the following item.

Plants grow in various environments. Some plants, like mangroves, grow in salty wetlands. Mangroves have specialized structures that prevent salt from entering their cells. Other mangroves have specialized glands that can excrete excess salt.

Glands that excrete salt in the mangroves are examples of