Which blood vessel carries blood from the heart to the lungs? MCQ with Answer and Explanation

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.

Explanation:
Phloem transports organic solutes (mainly sucrose) from source (leaves) to sink (roots, fruits) in a process called translocation, using sieve tubes and companion cells. Xylem transports water and minerals from roots upwards. Collenchyma and sclerenchyma are mechanical tissues providing support. Phloem is alive at maturity, while xylem vessels are dead. Companion cells regulate sieve tube activity.

Explanation:
Antonie van Leeuwenhoek was the first to observe and describe living microorganisms, including bacteria, using his single-lens microscopes. Robert Koch formulated Koch's postulates, a set of criteria to establish that a specific microorganism causes a specific disease. Alexander Fleming discovered penicillin; streptomycin was discovered by Selman Waksman. Thus, statements 1 and 2 are correct.