The nucleus is a membrane enclosed organelle found in most eukaryotic cells,which stores the genetic material .
Answer:
smog
Explanation:
Photochemical smog is a mixture of pollutants that are formed when nitrogen oxides and volatile organic compounds (VOCs) react to sunlight, creating a brown haze above cities.
A cell that just fertilized has to divide 6 times to form a 64 cell blastomere.
<u>Explanation:</u>
Human reproduction begins with the fusion of male gamete sperm and female gamete ovum. The fusion of sperm and ovum forms the zygote that is diploid. The zygote then undergoes mitotic division to develop into embryo.
The zygote first divides into two and the two individual cells divide again to form four individual cells and so on. Thus the number of cells after each division can be represented by the equation 
where n is the number of divisions. in the question it is given that the blastomere has 64 cells.
n=6
This means that the fertilized cell has to divide 6 times to develop into 64-celled blastomere.
Answer:
<u><em>definition;</em></u>
enzymes are protein that catalyze speed up the biochemical reactions and are not changed during the reaction . the molecules at which enzyme work are called <em>substrate </em> and enzymes convert them into different molecules called products.
<em><u>benefits of enzyme in digestion ;</u></em>
enzyme lower the activation energy in several ways. they may alter the shape of substrate and reduce the requirement of activation energy . enzyme may also lower activation energy by bringing substrate in correct orientation to react . enzyme break down <em>carbohydrates, lipids and proteins </em>which are component of human food .In digestion larger molecules are broken into smaller molecules like amino acids ,simple sugars ,fatty acid ,vitamins ,salts and water to provide to cells. these molecules are a part of larger molecules like protein ,polysaccharids and lipids . enzymes like amylaze, lypase ,salivary amylase, pepsin ; it is a very strong protein digesting enzyme it is released in its inactive form pepsinogen which is converted into pepsin with the help of H-C-L hydrochloric acid it takes part in digestion in stomach
