The valves are responsible for preventing blood from flowing in the wrong direction, they are present in the veins, and the arteries don't need them because the aorta (biggest artery) pumps or in other words pushes it with such a force that no other force can change its direction, in the veins there is no structure present for pumping them as a result we have got valves so that they go in one direction...... the meaning of the word valve is to allow in one direction
The above is an example of a polygenic trait. This implies every prevailing allele "includes" to the declaration of the following predominant allele. As a rule, qualities are polygenic when there is a wide variety in the characteristic. For instance, people can be a wide range of sizes. Stature is a polygenic characteristic, controlled by no less than three qualities with six alleles.
There’s no answer choices but some characteristics of plants are that they are multicellular, eukaryotic and perform photosynthesis. Hope this helps. :)
Answer:
"Last week, you looked at both animal & plant cells. Both of these cells were diploid somatic eukaryotic. This week, you'll be looking at a different, but very important, type of cell: sexual cells. Two gametes, one from a female & one from a male, merge during the process of fecundation/fertilization to form a zygote. All in the organism will develop from this initial diploid cell".
Explanation:
There are two principal types of cells in the organism: Somatic cells that can not form any gametes, and germ cells that are in charge of gamete production. Both somatic cells and germinal cells will end their cycle dividing and becoming two daughter cells with the same genetic dotation after mitosis.
Somatic cells are any cell in the body excepting from sperm and egg cells. These somatic cells are diploid, they contain two chromosomes sets, each one inherited from each parental. Mutations in somatic cells affect the individual but the progeny does not inherit them. In this sense, these cells do not contribute to anything to inheritance terms through genetics.
Germ cells are the reproductive diploid cells, and the sexual organs (testes and ovaries) are the ones that produce them. These cells might suffer mitosis to form more sexual cells, and then a few of them suffer meiosis giving place to haploid gametes called sperm and egg cells through the gametogenesis process. Each germ cell produces 4 haploid gametes after meiosis.
Gametes´destiny is to merge in the process of fecundation, during which a new diploid cell called zygote emerges through fertilization. The zygote is a complete cell from the structural point of view that suffer successive mitosis to form the new organism.
C extinction because they need diversity to reproduce