Answer:
C) Biomagnification of mercury results in toxic levels of mercury high in the food chains.
Explanation:
Cell division is the process essential for growth and repair in multi-cellular organisms.
Injury to the tissue can activate surrounding cells to undergo cell division with the help of mitogens. Mitogens are the chemical substances which help in escalating mitotic divisions in the cells.
They act by activating the signal-transduction pathway which involve mitogen-activated protein kinase (MAPK).
Other possible manner could be the loss of density which could lead to the inactivation of contact inhibition. As there is a loss of cells during the injury, it makes an empty space which could also trigger or activate surrounding cell to start cell division.
In addition, at injury site the flow of blood also increases to transport various nutrients, clotting factors, growth factors etc. These increased nutrition and growth factors also speed up the process of mitosis.
Answer:
1) the genes and chromosomes do not double after each generations because parental sex cells are haploid and only contain one set of chromosomes. During fertilization the two cells fuse to form a diploid zygote with two copies of genes and chromosomes. For example a normal human has 46 chromosomes (2 copies of 23 chromosomes) during reproduction gametes which contain 23 chromosomes (haploid) fuse to form an offspring with the correct number of chromosomes ( 23 + 23 = 46).
2) offspring only receive one set of chromosomes from each parent so to maintain the chromosome number of humans. If this did not happen you would not be the same species.
Answer:
Water has a high Cohesion because of Hydrogen bonding. This is important as transport of water in the Xylem in plants relies on water being pulled up. Cohesion also gives the water a high surface tension, allowing small organisms, such as Pond Skaters, to walk along it.
Explanation:
Water molecules forming hydrogen bonds with one another. The partial negative charge on the O of one molecule can form a hydrogen bond with the partial positive charge on the hydrogens of other molecules. Water molecules are also attracted to other polar molecules and to ions.
Plants obtain the hydrogen they need from water molecules. Don't try to feed your plant hydrogen gas -- your plant wouldn't know what to do with it if you did. As long as they have water, plants can readily obtain all the hydrogen they need. :)