Animal Evolution and Complexity Quiz

What is the main reason why animals are considered simple or complex?

• Their ability to perform specialized functions

• Their tissue complexity

• Their ability to reproduce asexually

• Their size and shape

Which phylum of animals is considered the simplest due to their lack of specialized tissues or organs?

• Porifera

• Cnidaria

• Nematoda

• Platyhelminthes

What is the significance of the Cambrian Explosion in animal evolution?

• It resulted in the formation of the first human ancestors

• It marked a period of rapid innovation and diversification of animal phyla

• It led to the appearance of the first animals on Earth

• It caused a mass extinction event

Which phylum of animals is characterized by having an incomplete body cavity known as a pseudocoelom?

• Rotifera

• Nematoda

• Cephalopods

• Mollusca

What sets cephalopods apart from other molluscs?

• They have half a billion neurons and are highly intelligent

• They have a powerful muscle for shooting out water

• They have a single, spiraled shell

• They have a radula for scraping food