The atmosphere of Earth contains primarily which gas?

A.) Carbon dioxide

B.) Methane

C.) Oxygen

D.) Nitrogen

Why does my dog scream at me when I sleep?

Where does fertilization take place in conifers?

Which term does not represent a type of nebula? reflection dark emission spiral?

Control of gene expression A) allows bacteria to adapt to changing environments. B) is critical for development in multicellular organisms. C) allows bacteria to replicate without control. D) allows multicellular organisms to maintain homeostasis.

Monty was learning about life in the ocean. He made a food chain of some of the organisms he was studying.

Which vessels allows for oxygen movement into the tissues

What is the difference between a physical and a chemical change

What is described by binary fission? A) The way prokaryotes move. B) The way prokaryotes produce energy. C) The way prokaryotes reproduce. D) The way prokaryotes digest nutrients.

There are many different ecological and environmental conservation methods. Which is not a conservation method? A) water harvesting B) fishing seasons and limits C) limiting of clear cutting of forests D) wind and wave erosion on coastal areas

Explain when and how dire wolves became extinct.