What is a Fish?

Fish are the most diverse group of vertebrates, with more species than amphibians, reptiles, birds, and mammals combined. They are aquatic vertebrates with a backbone and skull, distinguishing them from invertebrates like jellyfish. Fish are cold-blooded, unlike warm-blooded aquatic mammals such as whales and dolphins. Key adaptations include gills for respiration, paired fins for swimming, and protective scales. Most fish reproduce externally. These adaptations have enabled fish to dominate aquatic ecosystems worldwide.

Which group of animals has more species than amphibians, reptiles, birds, and mammals combined?

• Reptiles

• Birds

• Fish

• Mammals

What sets fish apart from marine animals like jellyfish and starfish?

• They have lungs

• They have a backbone and skull

• They are warm-blooded

• They live on land

How do fish primarily obtain oxygen?

• Through gills

• Through lungs

• Through their fins

• Through their skin

What is a key difference between fish and aquatic mammals like whales?

• Fish are warm-blooded

• Fish have lungs

• Fish are cold-blooded

• Fish live on land

How do most fish reproduce?

• Internally, like mammals

• Externally, with eggs fertilized in water

• By budding

• By laying eggs on land