D. An element donates an electron to another element.
Answer:
Cross-link is a bond that links one polymer chain to another polymer chain. So cross-linked polymers are polymers that obtained when cross-link bond formed between monomeric units. The cross-linked polymer forms long chains, either branched or linear, that can form covalent bonds between the polymer molecules
Explanation:
Protista
A protist is any eukaryotic organism that is not an animal, plant or fungus. The protists do not form a natural group, since they sometimes exclude certain eukaryotes; but, like algae or invertebrates, they are often grouped together for convenience.
Community one because there are more different types of species and less of them.