Cancer is a complex group of diseases that occurs when cells grow out of control and crowd out normal cells. While going through the cell cycle, cells that are not properly produced commit apoptosis, which is controlled cell death. If a bad cell does not commit apoptosis, when it divides, the cell and its daughter cells will produces mutated genes, which will form a tumor.
The fundamental sequence of events in mitosis is the same as in meiosis (in meiosis it happens twice). Both processes include the breakdown of the nuclear membrane, the separation of genetic material into two groups, followed by cell division and the reformation of the nuclear membrane in each cells.
Fossil evidence suggests that the tiktaalik had lungs, which meant that it could breathe in air, instead of just water.
This trait allowed the tiktaalik to survive despite the low oxygen content of the shallow water because the tiktaalik would simply get its oxygen from the air. This selective advantage was passed on to the tiktaalik's offspring and over time, more amphibious creatures evolved with the ability to survive both on land and in water.
<u><em>half</em></u>
the cells resulted from meiosis (gametes) are haploid because they contain half the number of chromosomes found in somatic cells
