Which pair of statements best describes an essential amino acid?
a. it is an amino acid that contains peptide bonds. an example is proline.
b. it is an amino acid that contains nitrogen. an example is aspartic acid.
c. it is an amino acid that cannot be made by the body. it must be obtained from eating certain foods.
d. it is an amino acid that can be produced by the body. vitamin supplements maintain healthy levels.

The current thought on the structure of the cell membrane is: a. a static phosphate sandwich of lipids b. a fluid-mosaic of phospholipids and proteins c. a bilayer of proteins with static lipid molecules d. an impermeable bilayer of protein molecules e. a static and permeable phospholipid single layer

Anonnative species is best described as a species that a. does not normally live in an area b. has no permanent home c. is a poor predator d. increase biodiversity

Which of the following describes research that would be considered basic science? a. a farmer is trying to improve his crop yields by using a new kind of fertilizer. b. a college students is curious about the growth of desert pants in the presence of excess amounts of water. c. government officials are trying to prevent the spread of new strain of influenza virus. d. a doctor is trying to determine why a patient is feeling tried and sick.b.a college students is curious about the growth of desert pants in the presence of excess amount of water