Correct Answer: B. Scarcity

Explanation

Scarcity refers to the basic economic problem, the gap between limited – that is, scarce – resources and theoretically limitless wants. This situation requires people to make decisions about how to allocate resources efficiently, in order to satisfy basic needs and as many additional wants as possible

Correct Answer: C. careless

Explanation

(a)(i) Role of green plants are:

(1) They are called producers and are usually most abundant

(2) They mark the beginning of food chain

(3) Green plants can produce carbohydrates during photosynthesis

(4) They use carbon dioxide and water

(5) They harness, utilize or store light energy in the presence of light.

(ii) Role of herbivores:

(1) Herbivores are the primary consumers.

(2) They normally feed or depend directly on plant materials for food.

(3) They build up energy or food for herbivores.

(iii) Role of carnivores:

(1) They are the secondary consumers and are fewer in number

(2) They feed on herbivores or other animals for energy

(3) They are referred to as flesh eating animals

(iv) Role of Decomposers:

(1) They are also called tertiary consumers. They depend or feed on dead organic materials or saprophytes for energy.

(2) They help in the recycling of nutrients.

(b) Description of carbon cycle:

(1) Plants and animal respiration release carbon (iv) oxide to the atmosphere

(2)Plants are eaten by herbivores

(3) Herbivores are eaten by carnivores

(4) Dead organisms decay to release carbon (iv) oxide into the atmosphere

(5) Bacteria respire on some materials they absorb and release carbon (iv) oxide to the atmosphere

(6) Burning of plant or fossils or fuel release carbon (iv) oxide to the air

(7) Carbon (iv) oxide is found in ocean or large body of water, due to respiration which is released when required to maintain the balance.

(8) Green plants absorb atmospheric carbon (iv) oxide to produce food eaten by animals.

(9) Carbon (iv) oxide from the atmosphere dissolves in the ocean or large body of water.

Carbon cycle

Correct Answer: C. l and lll only

Correct Answer: D. 0.976

Explanation

\(P(\text{at least one solves the problem}) = 1 - P(\text{none solving the problem})\)

= 1 - (0.4)(0.3)(0.2)

= 1 - 0.024

= 0.976

Correct Answer: A. demographic evironment

Correct Answer: B. Hebron to Jerusalem

Correct Answer: A. Abwa

Explanation

(a) Methods of measuring the national income of a country are:

(i) Output method: This method measures the total money value of all goods and services produced in the country in a year. In order to avoid double counting, the figures are collected on the basis of value added.

(ii) Expenditure method:The expenditure approach calculates the total amount spent on consumption and investment purposes during the year. It is the total amount spent on goods and services by individuals, the government and firms.

(iii) Income method:This is obtained by adding incomes received by all the factors of production. The incomes to be added include workers' earning, profits of entrepreneurs, rents on land, etc. Transfer payments such as payment to old people, beggars are not included.

(b) Problems associated with measuring national income include:

(i) Incomplete information: Income returns are inaccurate and incomplete.

(ii) Double counting.

(iii) Inflation which changes the value of money upsets the calculation.

(iv) Subsistence production, i.e. housewife, production of goods for one's family.

(v) Unpaid goods and services, e.g. housewife, housekeepers.

(vi) Illegal transactions like drug peddling, smuggling etc.