CJHS 7 Science Ch. 13

Insecticides do not pollute the environment. 

• True
• False

Both mollusks and segmented worms have an open circulatory system. 

• True
• False 

Insect pests destroy more than food crops. 

• True 
• False 

All mollusks have shells. 

• True 
• False 

Cephalopods are the largest group of mollusks. 

• True 
• False 

Echinoderms are invertebrates that live in the ocean. 

• True 
• False 

Leeches can live only by sucking blood. 

• True
• False 

Leeches secrete a substance that prevents blood from clotting. 

• True
• False 

__________ that have two shells, include clams and scallops. 

• Gastropods
• Bivalves
• Cephalopods 

What kind of arthropod has exactly eight legs? 

• arachnid
• centipede
• crustacean