The Earth is about years old, and life has existed on Earth for about years.

Invasive species are one of the major threats to biodiversity. these species multiply quickly and compete with native species for food, sunlight, spac and other resources. on the map, determine the area where native species will have limited resources available to them due to invasion threat from invasive species threat very low low medium high very high

The term used to describe a disease-causing microorganism isa. virus.b. infection.c. pathogen.d. microbe.e. bacterium.

How can antibodies "remember" a particular bacterial invader or "antigen" on that invader?