Question

Write short note on any two: (i) Double fertilization (ii) Sewage treatment (iii) Control of Pneumonia

Hint:

Double fertilization is unique to angiosperms. Sewage treatment = Primary + Secondary stages. Pneumonia can be prevented by vaccination and treated with antibiotics.

Answer 1

(i) Double Fertilization: - It is a unique feature of flowering plants (angiosperms). - When a pollen tube enters the embryo sac, it releases two male gametes. \[\begin{array}{rl} \bullet & \text{One male gamete fuses with the egg cell to form a diploid zygote (2n) → Syngamy.} \\ \bullet & \text{The other male gamete fuses with two polar nuclei to form a triploid (3n) endosperm nucleus → Triple fusion.} \\ \end{array}\] - Since two types of fertilization events occur (syngamy + triple fusion), it is called double fertilization. - Significance: Endosperm formed provides nourishment to the developing embryo. (ii) Sewage Treatment: - Sewage treatment is a process of removing contaminants from wastewater before releasing it into water bodies. It has two main steps: \begin{enumerate} \item Primary Treatment: - Physical removal of large and suspended particles using sedimentation, filtration, and skimming. \item Secondary Treatment: - Biological treatment using aerobic microbes in aeration tanks, which degrade organic matter. - Sludge formed is anaerobically digested in biogas plants to produce methane. \end{enumerate} - Importance: Prevents water pollution, protects aquatic life, and recycles waste into biogas and manure. (iii) Control of Pneumonia: - Pneumonia is a serious disease caused by bacteria like Streptococcus pneumoniae or fungi/viruses. - Symptoms: Inflammation of alveoli, fever, cough, chest pain, and difficulty in breathing. - Control and Prevention: \[\begin{array}{rl} \bullet & \text{Vaccination against pneumococcus.} \\ \bullet & \text{Antibiotics (penicillin, erythromycin) for bacterial pneumonia.} \\ \bullet & \text{Good nutrition, hygiene, and avoiding overcrowded places reduce infection chances.} \\ \end{array}\]