Question 1
Name the tissues whose cells are thickened with:
- Cellulose and pectin
- Lignin
Answer
- Collenchyma
- Sclerenchyma
Question 2.
The diagram below represents a fern.
- Name Parts labeled A and B
- A
- B
- To which division does the plant belong?
Answer
-
- A - Sori
- B - Rhizome
- Pteridophyta
Question 3
State three measures that can be taken to control infection of man by protozoan parasites.
Answer
- Improving sanitation/hygiene
- Using insecticides to kill vectors
- Avoiding indiscriminate sexual intercourse
- Clearing bushes/tall grass around the house
- Using insecticides to kill vectors
- Avoiding indiscriminate sexual intercourse
- Clearing bushes/tall grass around the house
Question 4
Explain how the following factors hinder self pollination in plants
- Protogyny
- Dioecism
Answer
- Protogyny - Stigma matures earlier and is ready to receive pollen grains before the anthers are ready
- Dioecism - Male and female gametes occur in separate plants.
Question 5
Explain the likely effect on humans and other organisms of untreated sewage discharged into water body that supplies water for domestic use.
Answer
Contains disease – causing micro-organisms which may cause outbreak of water borne diseases; faecal material is broken down by saprophytes leading to depletion of dissolved oxygen thus suffocation of aquatic organisms; breakdown of matter releases nutrients which enrich the water resulting in eutrophication.