Starvation.
Disease.
Weather.
Lack of mate.
Offspring dying.
Hunting.<span />
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).
Fact, BRCA genes help with cell division in the breast and prostate regions. Therefore, if they are mutated, the cell division process wouldn't function normally and possibly end up in cancer since the BRCA genes tend to be tumor suppressors (cancer is a malignant tumor).
