Cells are surrounded and protected by

Plasma membrane or cytoplasm

Explanation:

your answer is outer lining

mujhe aisa lga｡◕‿◕｡

clumped distribution, because you'de have all of the population gathered in a relatively small are.

it's the most common because it provides protection and a mate for reproduction

example: humans, seeweed, cattles, etc.

the sugar-phosphate backbone forms the structural framework of nucleic acids, including dna and rna. this backbone is composed of alternating sugar and phosphate groups, and defines directionality of the molecule.