Although the expression of most genes is tightly regulated, some genes are expressed at roughly constant rates (i. e., constitutively). Which of the following genes would you predict to be constitutively expressed?
A. genes involved in the biosynthesis of tryptophan (an amino acid)
B. genes involved in the degradation of tryptophan
C. genes involved in the degradation of arabinose, a sugar
D. genes that that code for ribosomal RNAs
E. genes involved in the transport of maltose, a sugar, into the cell

The response is ribosomal genes. Ribosomes are cellular structures involved in assembling amino acids to form proteins, it thereby being necessary to generate sufficient ribosomal subunits in order to maintain the protein levels in the cell

answer: 20 percent

the fish culture has become a developing commercial practice in developing countries which is already prominent in developed countries of the world. the major fish protein demand is being supplemented in developing countries is   fishing to meet the needs of the growing population. therefore, in some developing nations, the percentage of animal protein from fish in the diet can be as high as 20 percent.