If an atom of Calcium has 21 electrons is it a...? A) isotope

B) calcium does not have electrons

C) normal, no charge

D) ion

D) ion

Explanation:

A stable atom of calcium has 20 electrons

in this image, you can see solar radiation going through ocean water.

no image, but probably absorption

the skeletons of most mammals reach a certain size and then stop growing. however, many animals, including some mammals, keep growing throughout their lives. kangaroos, for example, just keep growing and growing until they die. also, the longer an animal lives the greater the chance it might catch some deadly disease.