What elements are in hydroxyapatite, ca5(po4)3oh, a major compound in human bones and teeth?

Hydroxyapatite refers to one of the prime components of and an important element of usual teeth and bone. It forms the matrix of teeth and mineral of the bone. It is the hydroxyapatite molecule that gives the teeth and bones their rigidity. These molecules can combine together to produce microscopic clumps.  

About seventy percent of the bone comprises of the inorganic mineral hydroxyapatite that comprises calcium carbonate, calcium phosphate, calcium hydroxide, calcium fluoride, and citrate.  

fertilization, pictured in figure 24.23a is the process in which gametes (an egg and sperm) fuse to form a zygote. the egg and sperm each contain one set of chromosomes. to ensure that the offspring has only one complete diploid set of chromosomes, only one sperm must fuse with one egg. in mammals, the egg is protected by a layer of extracellular matrix consisting mainly of glycoproteins called the zona pellucida. when a sperm binds to the zona pellucida, a series of biochemical events, called the acrosomal reactions, take place. in placental mammals, the acrosome contains digestive enzymes that initiate the degradation of the glycoprotein matrix protecting the egg and allowing the sperm plasma membrane to fuse with the egg plasma membrane, as illustrated in figure 24.23b. the fusion of these two membranes creates an opening through which the sperm nucleus is transferred into the ovum. the nuclear membranes of the egg and sperm break down and the two haploid genomes condense to form a diploid genome.

explanation:

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.