A substance that can be used or prepared for use as food
<span>The proteins that are embedded in the cell membrane act as channels to transport substances in and out of the cell.</span>
The answer you are looking for is C.
The number of people who are carriers (heterozygous) for PKU if there are 33 of the 300,000 people in Corpus Christi, TX, have PKU is 15. Heterozygous or also called as zygosity refers to having the unlike genes or different genes.