Gases are constantly consumed and produced by cellular and metabolic reactions in most living things, so an efficient system for gas exchange between, ultimately, the interior of the cell(s) and the external environment is required. Small, particularly unicellular organisms, such as bacteria and protozoa, have a high surface-area to volume ratio.
Polyploid. (genetics) an organism or cell having more than twice the haploid number of chromosomes.Of a cell or organism having more than twice the haploid number of chromosomes; a polyploid cell; a polyploid species .Organisms that possess two sets of each chromosome.
Polyploidy. Polyploidy is a condition in which an individual has sets of chromosomes greater than the normal diploid number. There are number of key factors to help you remember: 1  The number of chromosomes making up one set is the haploid number = n. 2  The number of chromosomes making up two sets is the diploid number = 2n.