Consider statements about angiosperms: 1. They have enclosed seeds. 2. They exhibit double fertilization. 3. All angiosperms are trees. Which are correct? MCQ with Answer and Explanation

Explanation:
Robert Koch identified Mycobacterium tuberculosis as the causative agent of tuberculosis in 1882, applying his postulates. He also discovered the cholera bacillus. Pasteur worked on vaccines, Jenner smallpox, Lister antisepsis.

Explanation:
Primary succession begins on lifeless, barren substrates like bare rock, where no soil exists initially. Secondary succession occurs in areas where an existing community has been destroyed by disturbances like forest fires, floods, or logging, but soil remains. A climax community is the final, stable, and self-perpetuating stage of ecological succession, in equilibrium with the environment. Thus, statements 1 and 2 are correct.

Explanation:
Residual volume (RV) is the air left in the lungs (about 1.2 L) after a forceful expiration. This prevents lung collapse and ensures continuous gas exchange between breaths. Tidal volume is normal breath volume, vital capacity is the maximum exhaled after maximum inhalation, and inspiratory reserve volume is the extra air that can be inhaled beyond tidal volume.