Early cleavage divisions in most embryos are also rapid. One reason for this is that cleaving cells have a modified cell cycle, in which the two gap phases, G1 and G2 are completely omitted, and the cells cycle rapidly between M and S phases. In addition, because the major cytoskeletal systems of the cells are largely devoted to mitosis (microtubules) and cytokinesis (microfilaments) during rapid cleavage division, there is typically an antagonism between periods of rapid cell division and cell movement. Thus as the embryo approaches gastrulation, there is a tremendous slowing in the rate of division (note the slope of the curve at the right).
Answer:
Evolution explains how living things are changing today and how modern living things have descended from ancient life forms that no longer exist on Earth. As living things evolve, they generally become better suited for their environment. This is because they evolve adaptations.Feb 23, 2012Explanation:
The appropriate answer is d. a topographic maps. A topographic map shows the physical features of the earth's surface. A topographic map would therefore highlight features such as mountains, valleys, rivers and other landforms.
The height above sea level of these landforms are represented on the map by contour lines. These are lines on a map that show the height of the land. Colour is sometimes used to represent height if contours are not used.
<span>Body cell mutations cannot be passed on to offspring. This is because body cells do not contribute genetic material to SEX CELLS. C is your answer</span>
