Correct Answer: A. regime

Correct Answer: D. hadn't confessed earlier on, and wasn't trusted

Explanation

If he confessed earlier, she would have trusted him. However, he didn't confess, so he wasn't trusted.

Explanation

6(a) Effects of maize weevil on maize grains are: (i) destroys the endosperm, thereby, reducing the food value grains. ( (ii) reduces viability of infested grains as the embryos are damaged. (iii) reduces market value of infested grains. (iv) predisposes infested grains to other pathogenic microorganisms attack. (v) reduces the quantity of the maize grains and produce.

(b) General control measures of insect pests of grains in storage are: (i) Early harvesting of grains such as maize, guinea corn and cowpea reduces the level of infestation and damage in the field. (ii) Proper cleaning and fumigation of sores before grains are stored helps to reduce the level of infestation and damage. (iii) Storage of maize -cobs with or without the husks and guinea corn heads over fire places where they are regularly smoked has been found to be effective in controlling the insect pests (iv) Storage and fumigation of she in silos or sealed polythene bags/ containers. (v) maize cob stored in cribs and unthreshed guinea corn heads in rhumbus should be treated with insecticides such as Actellic 25 dust or liquid, (vi) Grains should be dried to reduce their moisture content to the desired level to kill the eggs and larva of pests.

(c) Insect vectors of crop diseases are: (i) groundnut rosette - aphid (ii) maize streak - Piercing and sucking insects e.g capsid or scale insects. (iii) cassava mosaic - white fly.

Correct Answer: A. I, II and III

Explanation

Let's analyze each statement:

I. A liquid boils when its saturated vapour pressure is equal to the external pressure.

This is the fundamental definition of boiling. At the boiling point, the vapor pressure of the liquid is strong enough to overcome the external pressure, allowing bubbles of vapor to form throughout the liquid.

• Verdict: True

II. Dissolved substances in pure water lead to increase in the boiling point.

This is a colligative property known as boiling point elevation. When a non-volatile solute is added to a solvent (like water), it lowers the vapor pressure of the solvent. To achieve boiling (where vapor pressure equals external pressure), a higher temperature is required.

• Verdict: True

III. When the external pressure is increased, the boiling point increases.

If the external pressure is higher, the liquid needs to reach a higher vapor pressure to boil. A higher vapor pressure corresponds to a higher temperature. For example, in a pressure cooker, the increased pressure raises the boiling point of water, allowing food to cook faster. Conversely, at higher altitudes where atmospheric pressure is lower, water boils at a lower temperature.

• Verdict: True

IV. Dissolved substances in pure water decrease the boiling point.

This statement contradicts statement II. As explained above, dissolved non-volatile substances *increase* the boiling point, not decrease it. Freezing point depression is when dissolved substances decrease the freezing point, but boiling point elevation is an increase.

• Verdict: False

Combining the true statements, we have I, II, and III.

Comparing this with the given options:

A. I, II and III

B. I, II, III and IV

C. I, II and IV

D. II, III and IV

The correct option is A.

The final answer is A

Correct Answer: D. fatty acids and glycerin

Explanation

Let Wale's present age = x.

Then Sonny's age = 2x

Four years ago, Wale = x - 4

Sonny = 4(x - 4) = 2x - 4

\(4x - 16 = 2x - 4 \implies 4x - 2x = -4 + 16\)

\(2x = 12 \implies x = 6\)

Sonny = 2x = 2(6) = 12 years

In z years' time, the sum of their ages = 66

Wale = 6 + z

Sonny = 12 + z

\(6 + z + 12 + z = 66 \implies 18 + 2z = 66\)

\(2z = 66 - 18 = 48 \implies z = 24\)

Therefore, in 24 years time, the sum of their ages will be 66.

Correct Answer: B. guinea savanna

Correct Answer: A. simplicity

Correct Answer: A. longer than \(10^{-6} m\).

Explanation

The range of wavelengths for infrared waves is given as \(10^{-3}\) m to \(10^{-6}\)m. This means that the wavelength of the radiation is longer than \(10^{-6} m\) but shorter than \{10^{-3} m\). Therefore, the only correct option is that the wavelength is longer than \(10^{-6} m\).

Correct Answer: D. family