Body Systems and Senses — Answer Key
Part A: Fix the Sentence
Each sentence has an error. Rewrite it correctly on the line.
1. Fix the sentence:
Owls has terrible night vision and cannot hunt after dark.
Corrected: Owls have excellent night vision and can hunt after dark.
Owls have large eyes packed with rod cells, giving them sharp night vision for hunting prey in darkness.
2. Fix the sentence:
Dogs smells weakly and rely mostly on their eyesight.
Corrected: Dogs smell strongly and rely mostly on their sense of smell.
Dogs have about 300 million scent receptors in their noses, helping them detect smells far better than humans can.
3. Fix the sentence:
Bats uses echolocation by sending out light beams in caves.
Corrected: Bats use echolocation by sending out sound waves in caves.
Bats emit high-pitched sound waves that bounce off objects, helping them locate prey and avoid obstacles in the dark.
Part B: Fill in the Blank
Write the missing word or number on each line.
1. An owl's large eyes help it see well at night when hunting mice.
Owls are nocturnal, so their eyes are adapted to gather light at night for hunting.
2. A dog uses its sense of smell to track scents on the ground.
Dogs have a powerful sense of smell that lets them follow scent trails left by other animals.
3. Bats use echolocation to find insects by listening to echoes bouncing back.
Echolocation lets bats hunt in total darkness by interpreting sound echoes that return from nearby objects.
4. Animals have specialized senses that help them survive in their environments.
Each species has senses suited to its habitat, helping it find food, avoid danger, and communicate.
Part C: Short Answer
Answer each question in one or two complete sentences.
1. Why are owls good at hunting at night?
Sample answer: Owls have very large eyes with many rod cells, which help them see clearly in low light at night.
Large eyes and many rod cells allow owls to detect tiny movements in dim light, making them skilled night hunters.
2. How do bats find food in the dark?
Sample answer: Bats use echolocation by sending out sound waves and listening to the echoes that bounce back from insects.
Echolocation lets bats build a sound map of their surroundings so they can catch flying insects in complete darkness.