There is no likeness between him and his brother.

Analyze the question: The underlined word is "likeness" (the underline isn't shown, but "likeness" is the only word that fits the options). We need the word opposite in meaning to "likeness".

Explain the concept: "Likeness" means resemblance or similarity. Its antonym is a word meaning difference or lack of resemblance.

Work through the options:

• A. unlikeness: This does mean the opposite of likeness (a lack of resemblance), but it is just the word "likeness" with a negative prefix. It is rarely used and is a weak choice.
• B. likelihood: This means probability or chance. It looks like "likeness" but has no connection in meaning.
• C. dissimilarity: This means difference or lack of resemblance. It is the standard opposite of likeness and similarity.
• D. affinity: This means closeness, resemblance, or natural attraction. It is a synonym of "likeness", not an antonym.

Between A and C: Both fit the meaning, but JAMB generally expects the standard, well-established antonym. "Dissimilarity" is the common word for the opposite of "likeness".

Answer: C. dissimilarity

Tip: In antonym questions, first eliminate synonyms (here, D "affinity") and look-alike words (here, B "likelihood"). If two options seem to fit, choose the more standard, widely used word over a rarely used or newly formed one like "unlikeness".