Consider statements about photosynthesis: 1. Light reactions occur in the grana. 2. The Calvin cycle occurs in the stroma. 3. Oxygen is released from CO2. Which are correct? MCQ with Answer and Explanation

Explanation:
Phototropism (positive in shoots) is caused by the migration of auxin to the shaded side of the shoot, promoting cell elongation more on that side, causing the shoot to bend towards light. This asymmetric auxin distribution was demonstrated by Went's experiments. Auxin is sensitive to light and moves laterally. This is a growth response to directional light.

Explanation:
Typhoid is caused by the bacterium Salmonella typhi, transmitted through contaminated food and water. Influenza (flu) is a viral disease, malaria is protozoan (Plasmodium), AIDS is viral (HIV). Common bacterial diseases include cholera, tuberculosis, diphtheria, tetanus. Typhoid fever is characterized by prolonged fever, headache, and rose spots on the skin. Widal test is used for diagnosis.

Explanation:
Robert Hooke observed thin slices of cork under a microscope he designed and saw honeycomb-like compartments which he termed 'cells' in his 1665 book 'Micrographia'. Leeuwenhoek discovered living cells (bacteria, protozoa). Brown discovered the nucleus (1831), and Virchow proposed that all cells arise from pre-existing cells (1855). Hooke's cells were dead, empty cell walls of cork.