Correct Answer: C. than

Explanation

The correct answer is C. than.

The phrase No sooner... than... is a common correlative conjunction used to indicate that one event happens immediately after another.

The structure is: No sooner + had + subject + past participle + than + subject + past tense verb.

In your sentence: No sooner had the examination ended than the students started vacating the halls of residence.

Explanation

(a) Explanation of causes of damage to maize during storage(i) High humidity- High humidity often leads to mould formation, thus reducing the quality of maize

(ii) Pests -The presence of pests reduces the quality of maize - Pests reduces the quantity of maize - Reduces the viability of seeds; thus the germination rate

(iii) Pathogens -The presence of moulds and other fungi reduces the quality of stored maize

(iv) Heat generated during storage - This enhances the formation of moulds, thus reducing the quality of maize.

(v) Poor Storage Structure - Leaking roof allows water to get into the stored maize; thus leading to mouldiness - Allows infestation of pests and pathogens

(b)(i) Possible offspring that could result from the cross

(ii)1. Genotypic ratio of the offspring 1:2:1

2. Phenotypic ratio of the offspring 3:1

(c) Menders laws of inheritance -First law (Law of segregation of genes) Genes occur in pairs and are transmitted independently from one generation to anotherSecond law (Law of independent assortment of genes)Genes for different traits are sorted separately from one another such that the inheritance of one trait is not dependent on another

(d) Forage grasses - Guinea grass/Panicum maximum - Stubborn grass/Eleusine indica - Elephant grass/Pennisetum purpureum -Southern gamba grass/Andropogon tectorum - Rhodes grass/Chloris gay ana -Bermuda grass/Bahana grass/Cynodon dactylon -Spear grass/lmperata cylindrica -Carpet grass/Axonopus compressus -Kikuyu grass/Pennisetum clandestinum -Northern gamba grass/Andropogon gayana - Giant star grass/Cynodon plectostachyus

Correct Answer: A. fragility

Correct Answer: B. the Ammonites

Correct Answer: D. 1.48

Correct Answer: C. depopulation of urban centres

Correct Answer: A. \(\frac{1}{10}\)

Explanation

P(Kodjo passing) = \(\frac{3}{4}\); P(Adoga passing) = \(\frac{3}{5}\)

P(Kodjo failing) = \(\frac{1}{4}\); P(Adoga failing) = \(\frac{2}{5}\)

P(both fail) = \(\frac{1}{4} \times \frac{2}{5}\)

= \(\frac{1}{10}\)

Correct Answer: C. lenticels

Correct Answer: B. contempt

Correct Answer: C. have variable oxidation states

Explanation

The main characteristic feature of transition metals is that they can exhibit multiple stable oxidation states. This is due to the fact that they can use both their outermost s-electrons and their inner d-electrons for bonding.

Let's evaluate the options:

• A. have the same atomic size: This is incorrect. Atomic size varies across the period and down the group for transition metals, although there can be some relatively similar sizes in the middle of a period (e.g., due to the lanthanide contraction for the 5d series).

• B. are reducing agents: While many transition metals are good reducing agents (they tend to lose electrons), this is a general characteristic of most metals. It's not a unique or primary defining feature that distinguishes them from, say, alkali metals or alkaline earth metals, which are even stronger reducing agents.

• C. have variable oxidation states: This is a highly characteristic and distinguishing feature of transition metals. For example, iron can be Fe(II) or Fe(III), manganese can exhibit +2, +3, +4, +6, and +7 oxidation states, and copper can be Cu(I) or Cu(II). This property arises from the ability of their (n-1)d and ns electrons to participate in bonding.

• D. form ions easily: This is true for all metals; metals generally have low ionization energies and readily lose electrons to form positive ions. It's a general property of metals, not a distinguishing characteristic of transition metals compared to other types of metals.

Therefore, the most accurate and characteristic feature is having variable oxidation states.

The final answer is C