Question 6
(a) What is meant by:
(i) biennial plant; [2 marks]
(ii) perennial plant? [2 marks]
(b) State four characteristic features of carnivorous plants. [4 marks]
(c) Give one example each of seeds that undergo the two types of germination.
(d) Complete the table below by stating one use each of the listed structural adaptive features of organisms.
(e) State three factors that affect tolerance ranges of organisms in a habitat. [3 marks]
(f) (i) Name the laws that explain energy flow in an ecosystem. [1 mark]
(ii) State the laws named in 6(f)(i). [4 marks]
(g) An individual burgled the Cash Office in an establishment and stole some amount of money. Accidentally, the burglar had a cut on the finger and blood smeared the table.
State two tests that could be used to identify the burglar. [2 marks]
(h) Name two diseases of the liver. [2 marks]
Observation
This question was compulsory.
Question 6(a), a few candidates could explain biennial and perennial plants.
In 6(b), some candidates could not state the characteristic features of carnivorous plants.
In 6(c), poor spellings of hypogeal and epigeal made candidates lose the marks. Some candidates could give examples while majority mixed them up.
In 6(d), candidates’ performance was average.
In 6(e), candidates could not state the factors that affect tolerance ranges of organisms in a habitat, while those that attempted it lost marks to wrong spellings.
In 6(f), some candidates could name the law that explains energy flow in an ecosystem but could not define the laws.
In 6(g), candidates also lost marks to spelling errors.
In 6(h), many candidates lost marks to the wrong spelling of liver diseases.
The expected answers are:
(a) (i) Biennial Plants
Require two growing seasons; to complete their life cycle; in the first season they grow/mature/ store food; in the second season, they reproduce/produce foods/flowers/seeds and die.
(ii) Perennial Plants
Live for more than two years/ growing seasons; to complete their life cycle; they produce fruits every year before they die.
(b) Characteristic Features of Carnivorous Plants
- They feed on/trap/digest/kill insects;
- Flowers are scented to attract insects;
- They grow on soil deficient in nitrogen/acidic/water logged/ peaty localities.
- Flowers are brightly coloured to attract insects;
- They possess nectar;
- Some have leaves modified into pitchers/bladder/hair-like tentacles;
- They secrete proteolytic enzymes to digest the insect.
(c) Examples of seeds that undergo germination
(d) Uses of the listed structural adaptive features of organisms
(e) Factors that affect tolerance ranges of organisms in a habitat
- Salinity;
- pH;
- Temperature;
- Air/oxygen;
- Light availability/intensity;
- Presence/absence of predators;
- Water/rainfall;
- Nutrient/food
- Wind
- Topography
(f) (i) laws to explain energy flow
Thermodynamics (First and Second)
Note: Spellings must be correct to score.
(ii) Laws of thermodynamics
First law of thermodynamics states that energy can neither be created nor destroyed;
but can only be transformed/transferred from one form to another.
Second law of thermodynamics states that every process of energy transfer/transformation
from one form to another is accompanied by a loss of energy; in the form of heat/energy
formed can never be 100% efficient.
(g) Tests that could be used to identify the burglar
- Blood group test;
- Fingerprints;
- DNA test.
(h) Diseases of the liver
Hepatitis, Cirrhosis, Cancer of the liver, Gallstones; amoebic liver abscess.
Note: Spellings must be correct to score.