When only one pair of shared electrons is involved in a covalent bond, the linkage is called a bond.

When only one pair of shared electrons is involved in a covalent bond , the linkage is called a single bond.

plants need sunlight, water, and carbon dioxide to make food. plants use the raw materials of water, nutrients they absorb from soil, and carbon dioxide to make sugars the plant can use. energy from the sun and chlorophyll are also needed.