to act or operate normally

very tiny single-celled organisms

the end of or the dying out of a type of organism

a community of organisms and their physical environment

to soak up or take in

ready to be used

two things influence or act on each other

any living thing

people who study science and use the knowledge in their work

having to do with the tropics

the weather conditions that are typical of a certain region over a period of years.

single-celled organisms that have some plant, animal, or fungus characteristics

things that someone or something needs

a plant-like organism without leaves, flowers, or green coloring