Following fertilization, the single-celled zygote undergoes cleavage, where it is then divided into numerous tiny cells. After 3 to 4 days of fertilization, the cleavage produces a 16 celled embryonic stage known as morula, which is contained within the zona pellucida.
After about 4-5 days of fertilization, cleavage produces a sphere mass of cells known as blastomeres, which is covered by a layer known as trophoblast and has a fluid-filled cavity in the center, known as blastocoel. The blastomeres then migrate inward, changing position and undergoing rearrangements. This is known as gastrulation.
Gastrulation then causes the development of three germ layers: ectoderma, endoderma, and mesoderma. The interaction of cells and the rearrangement of tissues and organs occurs only after the formation of germ layers.
Answer:
Geosphere is the one that includes its mantle, core and crust.
Answer: Flowers are the reproductive organs of plants. Each pea plant flower has both male and female parts. The anther is part of the stamen, the male structure that produces male gametes (pollen). The stigma is part of the pistil, the female structure that produces female gametes and guides the pollen grains to them.
Explanation:
Answer: B. beta
Explanation:
Sickle cell anemia is a inherited disorder which occur due to mutation of gene responsible for synthesis of hemoglobin protein. Typically the gene which is responsible for synthesis of beta-globin protein which make the beta chains in the hemoglobin is affected by the mutation. As a result of this the red blood cells acquire a shape of sickle rather than round. Pain, cold, stress, dehydration and illness are the symptoms associated with this disorder.
