As an end product, lactic acid is produced which makes the milk thicker and finally converts it into curd.

The iron minerals that are at present used as ores are hematite, magnetite, limonite, and siderite.

The correct answer is the Glyptal. The term "natural polymers" refers to compounds that are produced naturally. Glyptal is a synthetic polymer and does not exist in nature. The polymer substance formed from glycerol and phthalic acid is known commercially as glyptal.

The Aryabhata spacecraft, named after the famous Indian astronomer, was India's first satellite; it was completely designed and fabricated in India and launched by a Soviet Kosmos-3M rocket from Kapustin Yar on April 19, 1975.

Thus, a metal used in storage batteries is Lead.

For short durations of time, sounds up to a 120 dB are bearable and also considered safe by the world health organization, but again, listening to sounds at such high frequencies at regular intervals of stretched time durations is totally unsafe and makes the ears vulnerable to permanent hearing loss.

An autotroph is an organism that can produce its own food using light, water, carbon dioxide, or other chemicals. Because autotrophs produce their own food, they are sometimes called producers. Most autotrophs use a process called photosynthesis to make their food.

Sleeping under a tree is not advisable at night, since photosynthesis does not occur, oxygen is not being produced by the trees. In addition to this, the trees continue respiring thereby causing the amount of carbon dioxide to be increased and the amount of oxygen to be reduced.