In human blood, the universal recipient blood group is: MCQ with Answer and Explanation

Explanation:
Nitrification is a two-step process in the nitrogen cycle where ammonia is oxidized to nitrates. First, ammonia (NH3) is converted to nitrites (NO2-) by bacteria like Nitrosomonas. Then, nitrites are converted to nitrates (NO3-) by bacteria like Nitrobacter. Nitrates are the primary form of nitrogen absorbed by plants. Denitrification is the reverse process, converting nitrates back to nitrogen gas.

Explanation:
Osteomalacia is the softening of bones in adults due to vitamin D deficiency, leading to inadequate mineralization of bone matrix. In children, the equivalent is rickets. Vitamin D aids calcium absorption. Deficiency may result from poor dietary intake, lack of sunlight, or malabsorption. Bones become weak and prone to fractures.

Explanation:
Growth hormone (somatotropin) stimulates protein synthesis, cell division, and growth of bones and muscles, especially during childhood. Thyroxine regulates metabolism, cortisol is a stress hormone from the adrenal cortex, adrenaline is from the adrenal medulla. GH deficiency leads to dwarfism; excess causes gigantism or acromegaly.