Consider statements about microorganisms: 1. Cyanobacteria are photosynthetic prokaryotes. 2. Mycorrhiza is a symbiotic association between fungi and plant roots. 3. Nitrosomonas is a denitrifying bacterium. Which are correct? MCQ with Answer and Explanation

Explanation:
The ozone layer, a region of high ozone concentration, is located in the stratosphere, approximately 15 to 35 kilometers above Earth's surface, where it absorbs harmful UV radiation. Chlorofluorocarbons (CFCs), once widely used in refrigerants and aerosols, release chlorine atoms in the stratosphere that catalytically destroy ozone molecules, leading to ozone depletion. Global warming is primarily caused by an increase, not a decrease, in atmospheric greenhouse gases like carbon dioxide (CO2), which trap more heat. Thus, statements 1 and 2 are correct.

Explanation:
Kwashiorkor results from severe protein deficiency with adequate calories, causing edema, pot belly, and skin lesions. Marasmus is overall calorie deficiency, beriberi thiamine.

Explanation:
The Cell Theory was proposed by Matthias Schleiden (1838) and Theodor Schwann (1839). Schleiden concluded that all plants are composed of cells, while Schwann extended this to animals, stating that all living organisms are composed of cells and their products. Rudolf Virchow later added that all cells arise from pre-existing cells.