Chemistry 2024 – Question 63

Chemistry 2024 – Question 63

Consider the following table

Substance Melting point / °C Boiling point / °C
P -78 -25
Q -8 40
R -6 150
S 44 280

Which of the substances is a liquid at room temperature and rapidly evaporates on exposure to air?

  1. P
  2. Q ✓
  3. R
  4. S

Explanation

Sexual reproduction involves flowers. Male part (stamen): anther produces pollen, filament supports it. Female part (pistil): stigma receives pollen, style connects to ovary containing ovules.

Pollination transfers pollen to stigma (by wind, insects, birds). Fertilization occurs when pollen tube grows down style; sperm meets egg in ovule. Fertilized ovule becomes seed; ovary becomes fruit.

Asexual/vegetative reproduction: runners (strawberry), tubers (potato), bulbs (onion), stem cuttings. Produces genetically identical offspring (clones). Faster but no genetic variation.