In humans, the yolk sac is the
site of origin for blood cells and primordial germ cells. The human yolk sac is
a membrane located outside the embryo and it is connected by a tube through the
umbilical opening to the embryo's midgut. The yolk sac serves as an early site
for the formation of blood and in time, is incorporated into the primitive gut
of the embryo.
The answer is b. to maintain the functions of the reproductive organs
Vitamin C is a water soluble vitamin that has a role in connective tissue. It produce and maintain collagen and has a role in wound healing. It also increase the iron absorption which makes orange juice a good drink for a meal with meat. Vitamin C will also protect and recycle vitamin e.
The data supports the fourth choice, that increasing air temperature and CO2 levels correlate with a decrease in dust concentration.
The first choice is unlikely to reflect dust concentration, and is more likely to be for air temperature. The second choice is false, because the dust concentration is more of a decreasing trend. The third choice is not true, as the spikes in air temperature and atmospheric CO2 concentrations seem to occur simultaneously, implying a positive correlation.
Well only plant cells have cell walls and cell membranes while animal cells only have cell membranes
Plants have cell walls, so cytokinesis cannot go on with a cleavage furrow, but instead, a cell plate forms across the cell in the location of the metaphase plate.
There is no distinct groove along the cell plate as the cell divides because of the rigid nature of the cell plate or new cell wall.
A plant cell divides differently from an animal cell which forms a clear cleavage furrow because it only has a flexible cell membrane and not a rigid cell wall like plants.
The cell plate in plant cells is formed by membrane bound vesicles which migrate to the center of the cell where the metaphase plate used to be and fuse together to form a cell plate.
