The substance naturally follow their concentration gradient however there must go through the protein channels because they are too large to squeeze through the cell membrane

the answer for this question would be d. glaciers

answer: 45

explanationyou have to add as well to be it could be

the diploid number of chromosomes is sometimes represented by the symbol 2n. for the fruit fly, the diploid number is 8, which can be written as 2n = 8, where n represents twice the number of chromosomes in a sperm or egg cell.