Simple Animals: Sponges, Jellies, & Octopuses - Crash Course Biology #22

What is a key characteristic that distinguishes sponges from most other animals?

• They can move freely in water.

• Their cells can transform into different types as needed.

• They have a complex digestive system.

• They are capable of photosynthesis.

Which of the following features is characteristic of Cnidaria?

• They have three germ layers.

• They possess a complete digestive tract with separate mouth and anus.

• They develop stinging cells called cnidocysts.

• They are sessile and cannot move.

Which germ layer is responsible for forming muscles, bones, and the circulatory system in triploblastic animals?

• Endoderm

• Ectoderm

• Mesoderm

• Epiderm

What is the primary function of a coelom in animals that possess one?

• It helps in photosynthesis.

• It stores and protects major organs.

• It provides structural support for the body.

• It aids in reproduction.

Which of the following adaptations appeared during the Cambrian Explosion?

• Soft-bodied animals that ate algae

• Animals with claws, spikes, and mineral skeletons

• Animals that only lived on land

• Simple, single-celled organisms

What is a key characteristic of Nematoda?

• They have a complete body cavity called a coelom.

• They are mostly large, segmented worms.

• They are pseudocoelomates with an incomplete body cavity.

• They only live as parasites in humans.

What is a unique reproductive characteristic of many Rotifera species?

• They reproduce sexually with both male and female individuals.

• They are all female and reproduce through unfertilized eggs.

• They reproduce by budding, like sponges.

• They lay eggs that require external fertilization.

Which of the following is a common characteristic shared by most mollusks?

• They all have a single, spiral shell.

• They possess a visceral mass, a muscular foot, and a mantle.

• They are exclusively filter feeders.

• They have tentacles and powerful muscles for jet propulsion.