Answer:
Cleavage is a process in which cell is divided into several parts without increasing in size. There are 4 stages of cleavage i. e. 2-cell, 4-cell, 8-cell and 16 cell stages. 2 cell embryo cleavage occurs after 30 hours of fertilization. 4 cell embryo cleavage occurs after 48 hours. 6 cell embryo cleavage occurs on third day of fertilization. 8 cell embryo cleavage occurs on fourth day of fertilization and more than 100 cells are formed.
Lit is a lichen,a combination of an algae and a fungi
Cell replication is meant to be a very regulated process. Messages are sent to the cell, telling it when to duplicate and when not to. When cells divide according to their natural plan, then there are no problems. However, when cells either do not receive those messages or misinterpret them, they can divide too fast and without pause. These renegade cells are what we call cancer cells.
Answer:
option d, b, c
Explanation:
Starch molecules taken into the mouth from food substances are processed to an extent of 30% of its digestion. this is carried out by a specialized protein/ an enzyme that is present in the saliva; called amylase or ptyalin. this enzyme acts on the substrate molecule which in this case is starch molecules and convert it into smaller chains of simple sugars that includes maltose and dextrin which is digested in the small intestine.
Answer:
The correct option is B (natural killer cells).
Explanation:
Natural killer cells: They are defined as the type of cytotoxic lymphocyte which are critical to the innate immune system. The NK cells play an important role in to provide rapid response to tumor formation, virus infected cells, and acting after three days of infection.
While cancer cells die, they release some antigens, than these antigens are recognized by the immune system, and later they are presented on the immune cells which are known as antigen presenting cells. So, if these cells are absent than they increase the chances of developing malignant tumors.
