Human birth rate peaked in the 1980s and has been slowly declining ever since. How is this expected to affect our population size over the next several decades?

Today, we are in the ________ geologic era.

An organism is considered truly multicellular when ________.

Today, we are in the ________ geologic era.

Human birth rate peaked in the 1980s and has been slowly declining ever since. How is this expected to affect our population size over the next several decades?

Most chordates are ________.

Perennials are ________.

Why are echinoderms and chordates closely related?

Perennials are ________.

An age pyramid with a broad base that quickly slopes up to a narrow top would be indicative of ________.