Explanation

(a)Problems of agricultural development in West Africa

• Inadequate basic amenities in rural areas
• Poor communication
• Inadequate agricultural education/illiteracy
• Use of crude tools
• Inadequate extension services
• Poor marketing system
• Inadequate farm inputs
• Incidence of pests
• Poor transportation network/bad roads
• Incidence of diseases
• Unfavourable land tenure system
• Rural-urban migration
• Negative attitude to farming
• Inadequate finance
• Inadequate storage facilities
• Inadequate processing facilities
• Environmental degradation e.g. erosion, pollution
• Unstable government policies and programmes
• Unpredictable climatic condition/climatic change

(b)Explanation of farming practices

(i)Crop rotation

Crop rotation is the type of cropping system whereby different types of crops are grown on

the same piece of land in successive years or seasons in a definite sequence or order so as

to maintain soil fertility following certain principles.

(ii)Mixed farming

Mixed farming is the system of farming in which crops are grown and animals are reared

on the same piece of land at the same time. Fence could be constructed to separate the

animals from the crops.

(c)Advantages of farm practices

(i)Advantages of crop rotation

• Properly planned rotation improves yield of crops;
• Conserves soil nutrients/adds nitrogen or nutrients to soil;
• Checks/controls soil erosion;
• Maximises the use of land;
• Helps to check/prevents the spread of diseases or pests;
• Allows for more efficient use of labour;
• Controls the growth of weeds.

(ii)Advantages of mixed farming

• Crop residues are used to feed livestock/farm animals;
• Farmer has access to both crop and animal produce;
• Animal manure can be added to the soil to increase its fertility;
• Provides a regular source of income to the farmer;
• Large animals like cattle and donkeys can be used for drawing implements to help in the cultivation of crops;
• Protects the farmer’s income in case of failure of any of the enterprises;

Correct Answer: B. Laterite soil

Explanation

(a)(i) Contract process

(ii) Vanadium (v) oxide (V\(_2\)O\(_5\))

(iii) 2SO\(_{2(g)}\) + O\(_{2(g)}\) \(\rightleftharpoons\) 2SO\(_{3(g)}\)

SO\(_{3(g)}\) + H\(_2\)SO\(_4\)\(_{(/)}\) \(\to\) H\(_2\)S\(_2\)O\(_7\)

H\(_2\)S\(_2\)O\(_7\)\(_{(/)}\) + H\(_2\))\(_{(/)}\) \(\to\) 2H\(_2\)SO\(_{4(aq)}\)

(b)(i) Dehydration is the removeal of the element of water from a compound with change in the chemical composition of the compcu while drying is the removal of associated water from a substance without affecting it chemical composition.

(ii) Concentrated H\(_2\)SO\(_4\) reacts with ammonia to form ammonium tetraoxosulphate (VI)

(iii) CaO or silica gel.

(c)(i) I. lead chloride (PbCl\(_2\))

II. K\(_2\)CO\(_3\) or Na\(_2\)CO\(_3\)

III. ZnO or Al\(_2\)O\(_3\)

(ii) I - Reaction of an acid with base (neutralization reaction)

- Reactiction of an acid with a metal

- Reaction of an acid with trioxocarbonate (IV)

- Double decomposition

- Direct combination of its constituent element

- A metal with halogens

(iii) - Evaporation

- Crystallization

(d)(i) Gay lussac's Law of coming volumes states that when gases react, they do so in volumes which are in simple ratio to one another and to the volumes of the products if gaseous, provided that the temperature and pressure remains constant.

(ii) C\(_2\)H\(_{4(g)}\) + 3O\(_{2(g)}\) \(\to\) 2H\(_2\)O + 2Cl\(_{2(g)}\)

1 cm\(^3\) of ethene requires 3cm\(^3\) of oxygen

12.5cm\(^3\) of ethene will require 3 x 12.5cm\(^3\) of oxygen = 37.5cm\(^3\)

Correct Answer: D. death of all the soldiers in the battlefield

Correct Answer: B. tendency towards secession

Correct Answer: D. made for

Correct Answer: A. 620

Explanation

d = -3 - (-7) = 4

S\(_{20}\) = \(\frac{20}{2}\){2(-7) + (20 - 1) 4}

= 10(- 14 + 76)

= 620

Correct Answer: B. 80^o

Correct Answer: D) social democratic party

Explanation

The correct answer is option D, which is the Social Democratic Party. This means that the Social Democratic Party did not participate in the 1979 general elections in Nigeria. It is important to note that the other options listed, Unity Party of Nigeria, National Party of Nigeria, and Peoples Democratic Alliance, all participated in the 1979 general elections in Nigeria.

It is also worth noting that the 1979 general elections in Nigeria marked the end of military rule and the beginning of the Second Nigerian Republic. The election was contested by five political parties, including the four options listed in the question. The election was won by the National Party of Nigeria and Shehu Shagari was elected as the President of Nigeria.

In summary, the correct answer to the question is option D, which is the Social Democratic Party. It is important to note that the other options participated in the 1979 general elections in Nigeria. The 1979 general election marked the end of military rule and the beginning of the Second Nigerian Republic.

Correct Answer: D. inverted and formed by the light from each point travelling in a straight line