Amolecule is a glycoprotein used to identify and distinguish white blood cells.
t-cell receptor
b-cell receptor
mhc i
cluster of differentiation

cluster of differentiation

Explanation:

Cluster of differentiation is protocol which is used for identification and the investigation of the cell surface molecules and thus providing targets for the immunophenotyping of the cells.

All of the T cells produce CD molecules which are the glycoproteins which can be used for the identification and the distinction between various types of white blood cells.

The two most important used for differentiation of classes are CD4 and CD8.

your answer is "the 1950's"

x would be the most and the least would be y because there are more fruit   and seeds than flock z has insects