Melanin is a(n) responsible for skin pigment. people who have albinism carry a mutant that does not make melanin. allele; gene gene; protein protein; allele allele; protein

The answer is protein; allele.  The protein melanin is specially produced by cells called melanocytes.  Melanin is critical in protecting against UV radiation from the sun that would cause damage to DNA and cause skin cancer. Being autosomal recessive for both alleles of the gene causes albinism.  

answer: c.

explanation:

many other transport proteins, often called pumps, move materials against a concentration gradient. active transport drives molecules across a membrane from a region of lower concentration to a region of higher concentration. this process, shown in figure 5.1, uses transport proteins powered by chemi- cal energy.