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).
- The integumentary system is the answer. It consists of the skin , hair, nails, glands and nerves.
Answer: Angiosperms are the plants which produce flowers for sexual reproduction.
Explanation:
In the angiosperm life cycle the following events occur:
1. Seed germination: Under suitable condition inside the soil obtain water, oxygen and minerals the seed germinates and from the two precursors plumule from where the stem emerge and radicle from where the root emerges.
2. Mature plant with flower: The plant gets matured with the develop of root and shoot and from the shoot the bud originates which produces the flower.
3. Pollination: During the process of pollination a mature pollen grain is transferred towards the female reproductive structure typically the stigma receives the pollen grain.
3. Fertilization of pollen with egg in ovary: The pollen is the male gametophyte which develops in the anthers which are the male reproductive structure of the flower and the egg or ovule is the female gamete which develops inside the ovary or female gametophyte. The fusion of male gametes provided by the pollen grain with that of the ovule is called as fertilization.
4. Formation of fruit with seed: After the fertilization process the ovules develop into seed and the ovary into fruit.
5. Seed dispersal: The fruit gets detached from the plant and it may get rotten and dried the dried seeds disperse and may germinate in favorable conditions.
