[ 279 ] Life Science GED ® TEST SCIENCE FLASH REVIEW • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • Refer to the following passage to answer the next three questions. In sexual reproduction, DNA is contributed by two parents with the goal of producing genetically distinct offspring. In most organisms, sexual reproduction includes a special form of cell division called meiosis, which results in the reduction of the number of chromosomes. Cells with only one complete set, or pair, of chromosomes are called haploid. Haploid cells are the reproductive cells, called either gametes or sex cells. Cells that contain two complete sets of chromosomes are called diploid. Almost all the cells in your body are diploid. Humans have 46 chromosomes or 23 pairs in each body cell. In sexual reproduction, two haploid cells, sperm and egg, combine to form a diploid cell, a zygote, which then develops into the offspring organism. Haploid and diploid are designated by the algebraic notations n and 2n. Either number can be calculated when the other number is known. The table shows some of the haploid or diploid numbers for various organisms. Organism Haploid Number (n) Diploid Number (2n) Chimpanzee 24 Earthworm 18 Honeybee 56 Human 46 Onion 16 How many chromosomes are in the gametes of an onion? What is the difference between the number of chromosomes in non-sex cells of a human and a chimpanzee? A. 1 B. 2 C. 22 D. 80