The DNA double helix is composed of two strands of DNA;

each strand is a polymer of DNA nucleotides.
Each nucleotide consists of a sugar, a phosphate group, and one of four nitrogenous bases.
The structure and orientation of the two strands are important to understanding DNA replication.

Depending on the organism the number of in a cell may change

Which ocean is on the eastern coast of north and south america? arctic ocean indian ocean pacific ocean atlantic ocean

Which of the following is a good definition for the word adaptation? question 1 options: a trait that an organism survive and reproduce in its environment. a change in an organism's environment. the way in which animals obtain food. a temperature change that can cause the extinction of plants and animals.