Animal Groups — Answer Key
Part A: Multiple Choice
Circle the letter of the best answer.
1. A frog starts life in water as a tadpole and later lives on land. What group does a frog belong to?
A) Fish
B) Reptile
C) Amphibian
D) Mammal
A frog belongs to the amphibian group. Amphibians start life in water as tadpoles, then develop lungs and legs to live on land as adults.
2. Which animal is an invertebrate?
A) Dog
B) Ladybug
C) Eagle
D) Goldfish
A ladybug is an invertebrate — it has no backbone. Dogs, eagles, and goldfish all have backbones, making them vertebrates.
3. A bat can fly. Why is a bat a mammal and not a bird?
A) It has fur and feeds its babies milk
B) It comes out at night
C) It lives in a cave
D) It has wings
A bat is a mammal because it has fur and feeds its babies milk. The ability to fly does not make an animal a bird — only feathers and egg-laying do that.
4. Which of these is true about ALL reptiles?
A) They all live in the desert
B) They all have shells
C) They are cold-blooded and have scales
D) They can all swim
All reptiles are cold-blooded and have scales. Not all reptiles live in the desert, have shells, or can swim, but every reptile is cold-blooded with scaly skin.
Part B: Fill in the Blank
Write the missing word on the line.
1. Amphibians begin life in water and later can live on land.
Amphibians begin life in water where they breathe with gills, and later develop lungs so they can live on land.
2. A spider has eight legs, so it is not an insect.
A spider has eight legs, so it is not an insect. Insects have six legs. Spiders belong to a different group called arachnids.
3. Fish, reptiles, birds, mammals, and amphibians all have backbones, so they are vertebrates.
Fish, reptiles, birds, mammals, and amphibians all have backbones, so they are all vertebrates. These five groups make up the main vertebrate classes.
4. Mammals are warm-blooded and have fur or hair on their bodies.
Mammals are warm-blooded and have fur or hair on their bodies. Fur helps mammals stay warm and is one of the key traits that defines the mammal group.
5. A crocodile is a reptile that lives near rivers and has tough scales.
A crocodile is a reptile that lives near rivers and has tough scales. Crocodiles are cold-blooded and one of the largest reptiles alive today.