1) D chromosomes
2) B a double helix
3)A chromosomes are made of DNA
4)A genes
A cellular membrane separates the interior of all cells from the outside environment.
Periderm is the corky outer layer of a plant stem which the plant creates as a result of an injury or infection so as to protect itself further. Protoderm is the thin layer which covers embryos, as well as the root and stems, and later produces epidermis, which is the outer layer of tissue of plants (anywhere where periderm doesn't cover them).
