In a snowy field some rabbits have white fur and some have brown fur, and foxes catch the rabbits they can see. Which rabbits survive better?

Two polar bears live on the same Arctic ice. One has a thick layer of fat and one has a thin layer. Which bear copes better with the cold?

Wolves hunt deer in one forest. Two deer live there, and one runs faster than the other. Which deer is more likely to survive?

On a brown twig bush, some stick insects are brown and some are bright green, and birds eat the ones they spot. Which insects survive better?

A cactus with a thick stem and a plant with thin, water-losing leaves grow in the same dry desert. The thin-leaved plant survives better.

A forest is cleared and the shady habitat disappears. Which animal is least likely to survive there now?

A river is so dark and murky that fish there cannot see food or predators. Which variation most helps a fish survive in that river?

A dry year comes to a meadow where some plants have deep roots and some have shallow roots. Which plants survive better?

A scientist finds a fossil of an animal that no longer exists anywhere on Earth. That animal is ___.

Some beetles in a field are green and some are brown. Birds eat the beetles they can see. Which beetles survive better in a grassy green field?

An animal that normally lives near a river is moved to a dry desert. What will most likely happen?

In one meadow the nectar sits deep inside every flower, and the birds there differ in beak length. What does this show about beak variation?

On a pale sandy beach some crabs have sand-colored shells and some have dark shells. Gulls eat the crabs they can see. Which crabs survive better there?

A hillside is swept by strong winds. Some sunflowers there have thick stems and some have thin stems. Which sunflowers survive better on that hillside?

In a dry season the only leaves left grow high in the trees. Some giraffes have longer necks than others. Which giraffes feed better there?

Mice hide under leaves in a dark forest. Some owls there hear better than other owls. Which owls catch more food in that forest?

In a windy meadow some plants make fluffy seeds and some make heavy, smooth seeds. Which seeds reach new ground farther away?

In a sunny meadow some flowers have large bright petals and some have small dull petals. Bees visit the flowers they notice. Which flowers make more seeds?

A desert cactus is planted in a wet, swampy field where the ground stays soaked. What will most likely happen to the cactus?

An ocean fish that lives in salt water is moved into a fresh water lake. What will most likely happen to that fish?