Correct Answer: D. it reduces the size of labour force

Explanation

(a)

(b)

(c)(i) The equation, \(3\sin x + 2\cos x = 0\) has solution where the curve cuts the x- axis, i.e. at A(x = 147°) and B(x = 325.5°).

(ii)First, rearrange \(2 + 2\cos x + 3\sin x = 0\) to have the main graph content \(3\sin x + 2\cos x\) on one side of the equation; i.e. \(3\sin x + 2\cos x = -2\).

Add the line \(y = -2\) to the graph. The line intersects the curve at the points (x = 180°) and (x = 292.5°). Hence, these are the solutions.

Correct Answer: B. medicine

Correct Answer: C) scavengers and predators

Explanation

Hyenas are animals that can feed on the remains of other animals that have been killed by other animals or they can also kill animals for food. This means that they can be described as animals that scavenge, which means they feed on dead animals, and as predators, which means they hunt and kill other animals for food. Therefore, the correct answer to this question is option C, which describes hyenas as scavengers and predators. It is important to note that scavengers play an important role in the ecosystem as they help to clean up dead animals and recycle nutrients back into the environment. Predators, on the other hand, are also important as they help to control populations of other animals and maintain a balance in the ecosystem. In contrast, herbivores are animals that feed on plants, while parasites are organisms that live on or in another organism and feed off of it, often causing harm to the host. Therefore, options A and D, which describe hyenas as herbivores, are incorrect. Option B, which describes hyenas as scavengers and parasites, is also incorrect as hyenas are not parasites. Option E, which describes hyenas as herbivores and parasites, is also incorrect.

Correct Answer: B. free-hold

Correct Answer: C. co-operative

Correct Answer: D. increase real per capital income

Explanation

(a) Salinity is the degree of concentration of salt solution in seas and oceans. This degree of saltiness of water is expressed in percentage or parts per thousand. The average salinity of ocean is 35.2 per thousand. Salinity varies across seas and oceans.

(b) Causes of variations in salinity of seas and oceans;

(i) The rates of evaporation

(1) The water around the high pressure belts of the Trade Wind Deserts between 20° and 30° N and S have high salinity because of the high rate of evaporation caused by high temperature and low humidity

(2) The temperature oceans have a lower rate of evaporation

(ii) The amount of fresh water added by precipitation, streams and icebergs:

(1) Salinity is lower in equatorial waters because of heavy rainfall and high relative humidity

(2) Oceans into which huge rivers like the Amazon, Congo and, Ganges flow have a lower salinity.

(3) Melting of icebergs add freshwater to Baltic, Arctic and Antarctic waters and thereby lower their salinity

(iii) The degree of water mixing by currents;

(1) Salinity is high in wholly or partially enclosed seas e.g. Caspian sea because the water does not mix free with the ocean water and is not penetrated by ocean currents

(2) in areas of inland drainage without links to the ocean continuous evaporation causes high salinity.

(3) In open oceans where currents freely flow salinity tends to be low.

(4) Free mixing of water by surface and subsurface currents reduces salinity of oceans.

(c) Importance of ocean to man;

(1) Oceans provide natural route by which goods from one continents reach another at lower possible cost

(2) Serve as sources of fish

(3) Serve as sources of minerals

(4) Employment opportunity

(5) Oceans are important recreation centres

(6) Oceans influence the climate of adjoining coastlands.

(7) Sea weeds for the making of cosmetic and fertilizers.

(8) Source of research in aquatic plants and animals.

Correct Answer: C. datum

Correct Answer: C. 5.00 x 10²rad s^-1

Explanation

The general equation for a wave travelling along the positive x-direction is given by:

y(x, t) = A sin(ωt - kx + φ)

where:

• A is the amplitude

• ω (omega) is the angular frequency

• k is the angular wave number

• φ is the phase constant

The given equation of the wave is:

y = 0.25 x 10^-3 sin (500t - 0.025x)

Comparing this equation with the general form y = A sin(ωt - kx), we can identify the corresponding terms:

• Amplitude (A) = 0.25 x 10^-3

• Angular frequency (ω) = 500

• Angular wave number (k) = 0.025

The question asks for the angular frequency of the wave motion. From the comparison, the angular frequency (ω) is 500.

The unit for angular frequency is radians per second (rad s^-1).

So, the angular frequency is 500 rad s^-1.

Now let's look at the given options:

A. 0.25 x 10^-3 rad s^-1

B. 0.25 x 10^-1 rad s^-1

C. 5.00 x 10² rad s^-1

D. 2.50 x 10³ rad s^-1

Our calculated value 500 can be written in scientific notation as 5.00 x 10². This matches option C.

The final answer is 5.00 x 10^2 rad s^-1