Answer:
Explanation:
Gas exchange occurs at the alveoli in the lungs and takes place by diffusion. The alveoli are surrounded by capillaries so oxygen and carbon dioxide diffuse between the air in the alveoli and the blood in the capillaries.
Answer:
Lining up of chromosomes in the cell
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Explanation:
Prophase begins with the Thickening of chromosome. Chromosomes are clearly visible inside the nucleus. each chromosome splits longitudinally to form two chromatids.
The centriole in the centrosome of animal cell divides into two. The centrosphere set the centrioles free. Centrioles develop very fine eye-lash like thread called aster rays. the two asters start moving towards the opposite poles. By the end of prophase they reach at the opposite poles.
3 inches per year best represents the average rate at which infants grow in height during the first four years after birth. The correct option among all the options that are given in the question is the second option or option "b". The other choices given in the question seems quiet absurd. So by the method of elimination, one can say that option "b" is correct.
