The selective pairing of adenine (A) with thymine (T) and guanine (G) with cytosine (C) is based on the number of hydrogen bonds established between one of the purine bases and the one pyrimidine bases
<span>Spirogyra, otherwise known as pond silk, is a type of algae that can be found in bodies of freshwater. The cells are long, unbranched, and cylindrical, being much longer than they are wide. There is no distinction between the basal and distal end, and they connect to each multiple times over to create the "silk" they are seen as; they also can reproduce sexually and asexually. Each cell has one nucleus and a cell wall composed of pectin surrounded by cellulose. Inside each cell is a very distinct spiraling shape of green, being chloroplast strands. It is these shapes for which the cells are named.</span>
Answer:
A. Sections of DNA that produce proteins that control an organism's characteristics
Explanation:
The other cells need these proteins in order to have a job, but they need to start from genes. Besides human traits, other organelles' dependence on them makes it vital to the life of a cell.
Monosacharides are used by plants and animals as a source of energy. your answer is d.
