Explanation

"Who" is used as the subject of a sentence referring to a person.

The sentence is asking about the person performing the action (knocking).

Explanation

A number divisible by 9 but not by 18 must be divisible by 9 but not by 2 (since 18 is a multiple of 2 and 9).

27 is divisible by 9 but not by 18, as 27 ÷ 9 = 3, but 27 ÷ 18 does not result in an integer.

Explanation

Corporal is a lower-ranking military position.

While Major, Captain and Colonel are officer ranks.

Therefore, Corporal is the odd one out in terms of rank level.

Explanation

1 / (2/3)

= 1 × (3/2)

= 3/2

Explanation

Substitute x = 1 and y = -1 into the expression:

13(x + y) = 13(1 + (-1)) = 13(0).

Therefore, 13(0) = 0.

Explanation

Given x = 1:

x² + 1/x² = 1² + 1/1²

= 1 + 1

= 2

Explanation

To solve, subtract 3/7 from 10/7:

10/7 - 3/7 = 7/7 = 1.

Therefore, the missing value is 1.

Explanation

• Teacher will allow the student to ask the unrelated question but kindly request that we discuss it after the class, so as not to disrupt the current lesson.
• It's important to encourage curiosity and engagement while maintaining focus on the topic at hand.

Explanation

Diffusion is the natural movement of particles from an area of higher concentration to lower concentration without external force.

It occurs in gases, liquids, and even solids to some extent.

Explanation

Lightning, along with high temperature and pressure, helps convert atmospheric nitrogen (N2) into usable forms like nitrates and ammonia.

These compounds are then absorbed by plants and enter the food chain, supporting life on Earth.