Question

Give reasons for the following
1) Glucose is absent in the urine of a healthy person .
2) All living things must excrete .
3) There is frequent urination in winter than in summer .
4) Blood flows in arteries in spurts and is under pressure .
5) Mature erythrocytes in human lack nucleus and mitochondria .

Answer 1

Answer:

Vitamin D3 (cholecalciferol) is synthesized in the skin by the reaction of 7-dehydrocholesterol with UVB radiation, present in sunlight with an UV index of three or more.

Answer 2

In physics and mathematics, the dimension of a mathematical space is informally defined as the minimum number of coordinates needed to specify any point within it. Thus a line has a dimension of one because only one coordinate is needed to specify a point on it – for example, the point at 5 on a number line.