Explanation

Mandela led the struggle against racial segregation (apartheid) in South Africa.

He became the country's first Black president in 1994.

Explanation

Explorer and Firefox are web browsers used to access the internet.

Such programs are categorized as application software, designed for specific user tasks.

Explanation

The sum of two whole numbers is always a whole number — this is called closure property of addition.

Whole numbers include 0 and all positive integers (0, 1, 2, 3, ...).

Explanation

"Which" is used for things, not people.

It should be "who is very ill" because it refers to a person (uncle Jamal).

Explanation

"Sang" is the past tense of the verb "sing" and shows the action performed.

A verb expresses an action, event, or state of being in a sentence.

Explanation

Explanation

Subject Identification:

"They" is the subject of the sentence, as it performs the action (knew).

"Both" is an adjective modifying "they," emphasizing the duo.

The subject is who/what the sentence is about.

Here, "they" (the duo) knew each other.

Explanation

The correct sentence should be:

"The old headmaster was walking along the road when he fell down."

Preposition Error:

"Below" means underneath (e.g., "below the surface"), which doesn’t fit the context.

"Along" is correct here, meaning moving in a line next to the road.

Explanation

Paint is a basic graphic program in Windows used for image editing and drawing.

It allows users to create, modify, and save images in different formats.

Explanation

To check if a number is exactly divisible by 4, we can check if the last two digits form a number that is divisible by 4.

2000: Last two digits are 00, which is divisible by 4.

Since 2000 ends in 00, it is exactly divisible by 4.