9.3 Invertebrates

What is the main characteristic of the invertebrates?

• They live only in water
• They don't have skeletons
• They don't have backbones
• They live only in land

Echinoderms (starfish, sea cucumber) have endoskeleton

• True
• False

Which of the following is not a group of invertebrates

• Sponges
• Mollusks
• Fishes
• Cnidarians

To which group of invertebrates do octopuses belong?

• Arthropods
• Echinoderms
• Cnidarians
• Mollusks

Invertebrates are the ___________ animals in the earth

• most abundant
• less abundant

Insects have

• 6 legs
• 8 legs
• 10 legs
• 2 legs

Arachnids have

• 6 legs
• 8 legs
• 10 legs
• 2 legs

Which of the following is one kind of worm

• Segmented worm
• Wood worm
• Flying worm
• Water worm

Arthropods have an _________ that protects them

• Exoskeleton
• Endoskeleton

All animals that have radial symmetry live in

• Water
• Land
• Water and Land