Science Review

Leopard seals are animals adapted to survive in the freezing conditions of Antarctica. Individual leopard seals vary in their different traits. Which of the following variations would give a leopard seal the greatest chance of surviving in its harsh environment?

• more spots on its coat
• thicker layer of blubber
• longer head
• wider, flatter teeth

The tip of a plant's root is covered by a root cap. The root cap produces a slimy, slippery substance. Which of the following is the MOST likely purpose for this substance? 

• absorbing water and nutrients in soil 
• reducing the plant's need for soil 
• helping roots grow through the soil 
• anchoring the plant to the soil 

Some dairy farmers want to increase the amount of milk produced by their cows. How can the farmers use selective breeding to increase milk production?

• By increasing the age of the cows that are bred
• By choosing cows that are high milk producers
• By limiting the number of offspring per cow
• By choosing cows that can produce milk after eating the most food

Penguins are unusual birds. They swim under water but do not fly. Penguins live in some of Earth's coldest climates, where they feed on sea animals. Unlike most birds which have bones that are hollow, a penguin has solid bones. This difference makes it easier for a penguin to — 

• dive deep under water
• find fish under water
• stay warm under water
• hold its breath under water

An acorn is a seed. Its shape is very different from the shape of a dandelion(flower) seed. Which of the following BEST describes the advantage of the SHAPE of the acorn?

• The acorn is more likely to stick to animal fur. 
• The acorn is less likely to attract hungry animals. 
• The acorn can be blown to a better growing location. 
• The acorn stores more materials to help it start growing. 

Mudskippers are a kind of fish that have developed adaptations that allow them to survive outside of the water and travel from one water source to another. What environmental condition most likely led to these adaptations?

• lower temperatures
• frequent droughts
• larger predators
• increased precipitation

Sea turtles have a salt gland that empties into their eyes and makes them appear to be crying salty tears. This salt gland is an adaptation that allows the sea turtle to maintain its internal environment while living in the ocean. This adaptation MOST LIKELY helps the sea turtle by —  

• raising its internal body temperature to the temperature of ocean water 
• helping to get rid of extra carbon dioxide that builds up in its tissues 
• removes excess salt from the body
• making it easier for the turtle to see in the ocean

Rabbits in most areas have a brown coat. The arctic hare has a bright white coat in winter. How does the arctic hare's white color help it survive? 

• It makes the hare warmer during the summer. 
• It helps the hare blend into its background. 
• It makes the hare appear larger to predators. 
• It helps the hare stay warm during the winter. 

Which of the following provides the best explanation of why birds have hollow bones?

• Hollow bones provide more structure for walking stability.
• Hollow bones provide extra storage for food needed by birds in winter.
• Hollow bones provide balance so birds can float when swimming in water.
• Hollow bones provide strength with less mass.

Xylem is a plant tissue made up of elongated cells stacked end to end the length of the plant’s stem. Which function is xylem specifically adapted to perform in plants?

• help prevent water loss
• exchange gases with the atmosphere
• capture sunlight for photosynthesis
• transport water from roots to leaves