Which type of molecule is used as markers to similar cells recognize eachother
carbohydrate
nucleic acid
lipid
protein

The correct answer is carbohydrate.

Explanation:

Cell to cell recognition is the ability of a cell to recognize if one type of neighboring cell different from another. This event takes place

when complementary molecules on other cell surfaces interact. A receptor molecule on one cell surface binds to its ligand on neighboring cells. Carbohydrate chains present on the surface of cell membranes of cells help in similar cells to identify each other.

Carbohydrates present on cells recognized by complementary carbohydrates. Complex carbohydrates receptors and complementary carbohydrates are able to form pliable interaction systems.

Thus, the correct answer is carbohydrates.

"d.) carbon dioxide and hydrogen sulfide"