Humans are capable of only one mode of reproduction, i.e. sexual reproduction. Haploid sex cells (gametes) are produced so that at fertilization a diploid zygote forms. This tutorial is an in-depth study guide regarding male and female reproductive physiology...
This tutorial noted some of the physical and chemical factors that provide the framework of a running water community in which organisms in their favored ecological niches occupy. Learn how each of these factors affects lotic communities in this tutorial...