Housekeeping genes are constantly expressed because the proteins encoded by them is a

The correct option is D Helps in the general metabolism of the cell
Housekeeping gene is expressed in all the cells in normal and pathological conditions. The genes which are expressed in all cell types and almost all the time. These genes are called housekeeping genes. These genes code for constitutive proteins and are constantly needed for cellular activities. Housekeeping genes are basically used to maintain the basic functions in a cell. These proteins are required to build cytoskeleton, membranes, ribosomes and other organelles in cells. They are also required to catalyze vital chemical reactions, e.g. in glycolysis. So, the correct answer is 'Housekeeping gene'.