Katie wants to make ball-and-stick models of the four macromolecules. she has colored balls for each of the elements in these molecules, including the following.

red: hydrogen
black: carbon
purple: oxygen
green: nitrogen

in which macromolecule will she use the black, red, and purple balls in a ratio of 1: 2: 1

carbohydrates are the body's preferred source of energy.

clinically, some people often have repeated allergies, eczema and respiratory infections or other parts of the infection, in this case, in addition to some routine tests such as tests for white blood cells, immunoglobulin series, lymphocyte subsets, etc., the five immune immunoglobulin tests are also necessary.