Define: (i) Seed dispersal. (ii) Gestation. State the agents of seed dispersal. Differentiate between insect and wind pollinated flowers. How is the human embryo protected?

Here are the answers to question 5:

a) List four (4) water pollutants and five (5) air pollutants.

• Water Pollutants:
  • Sewage and wastewater
  • Industrial chemicals and heavy metals
  • Agricultural runoff (pesticides, fertilizers)
  • Plastic waste
• Air Pollutants:
  • Carbon monoxide ($\text{CO}$)
  • Sulfur dioxide ($\text{SO}_2$)
  • Nitrogen oxides ($\text{NO}_x$)
  • Particulate matter
  • Volatile organic compounds ($\text{VOCs}$)

b) Describe the effect of bush burning in the environment.
Bush burning releases large amounts of smoke, particulate matter, and greenhouse gases (like carbon dioxide) into the atmosphere, contributing to air pollution and climate change. It destroys vegetation and animal habitats, leading to a loss of biodiversity. The burning also degrades soil quality by destroying organic matter and beneficial microorganisms, making the soil more susceptible to erosion and reducing its fertility.

c) How can water pollution be controlled?
Water pollution can be controlled through several measures. Wastewater treatment plants should be used to treat domestic and industrial sewage before it is discharged into water bodies. Proper disposal of solid waste and hazardous materials prevents them from leaching into water sources. Implementing sustainable agricultural practices, such as reduced use of fertilizers and pesticides, minimizes runoff. Strict regulations and enforcement against illegal dumping and industrial discharge are also crucial.