AP BIOLOGY

Detailed explanation-1: -These figures are multiples of seven. As a result, the basic monoploid number 7 produces species that are diploid, triploid, tetraploid, pentaploid, hexaploid and octaploid. All of these other than the diploids are called polyploids. Natural populations rarely experience ploidy levels higher than tetraploids.

Detailed explanation-2: -Polyploids are common among plants, as well as among certain groups of fish and amphibians. For instance, some salamanders, frogs, and leeches are polyploids. Many of these polyploid organisms are fit and well-adapted to their environments.

Detailed explanation-3: -Cells (and their owners) are polyploid if they contain more than two haploid (n) sets of chromosomes; that is, their chromosome number is some multiple of n greater than the 2n content of diploid cells. For example, triploid (3n) and tetraploid cell (4n) cells are polyploid.

Detailed explanation-4: -The DNA content of a cell in the G1 phase is 2N (N is the number of chromosomes), also known as diploid, whereas the DNA content of a cell in the G2 phase is 4N (tetraploid).