What is the main way that biodiversity can be maintained (kept the same) in ecosystems? A
Introducing indicator species

B
Protecting habitats

C
Removing keystone species

D
Protecting crop lands

The large increase in atmospheric carbon dioxide in the last 50 years most likely comes from a. an increase in cellular respiration b. increased decomposition by bacteria c. an increase in the burning of fossil fuels d. an increase in photosynthesis

Amino acids contain the elements carbon, hydrogen, oxygen, nitrogen, and sometimes sulfur. of the 20 amino acids found in humans, 11 are called "nonessential" because they can be manufactured by the body when needed. which elements in these 11 amino acids are commonly obtained from the metabolism of sugar molecules?

People with one sickle cell allele are not likely to get malaria. what is this an example of?