The scientist who proposed the 'lock and key' model was: MCQ with Answer and Explanation

Explanation:
Insulin, secreted by the pancreas, promotes cellular glucose uptake, lowering blood sugar levels. Adrenaline (epinephrine) from the adrenal medulla triggers the fight-or-flight response, increasing heart rate and energy supply. Thyroxine, produced by the thyroid gland, requires iodine as an essential component for its synthesis; iodine deficiency causes goiter. All statements are correct.

Explanation:
The ozone layer is located in the lower portion of the stratosphere, about 15–35 km above Earth. It absorbs most of the Sun's harmful ultraviolet radiation. Troposphere is the lowest layer, mesosphere and thermosphere above. Ozone depletion by CFCs led to the Antarctic ozone hole.

Explanation:
Selman Waksman coined the term 'antibiotic' in 1942 to describe chemical compounds produced by microorganisms that inhibit or kill other microbes. Fleming discovered penicillin, Ehrlich developed the concept of chemotherapy, Domagk discovered sulfa drugs.