Explanation

Convection is the transfer of heat through the movement of fluids (liquids or gases) due to differences in temperature and density.

It does not occur in solids as the particles in solids are not free to move.

Explanation

Direct Speech repeats or quotes the exact words spoken by someone, often enclosed in quotation marks.

Example: She said, "I am going to the market."

Explanation

Given 0 ≤ A ≤ 90°, we're looking at the first quadrant of the unit circle where sine values range from 0 to 1.

The minimum value of sin A in this range occurs when A = 0°:

sin(0°) = 0

Explanation

Pi (π) is defined as the ratio of the circumference of a circle to its diameter.

Mathematically, π = Circumference ÷ Diameter.

Explanation

Modal verbs express ability, possibility, permission, or obligation.

Can, could, may, shall, should, must are classic modal verbs.

Explanation

A power set contains all possible subsets of a given set, including the empty set and the set itself.

Example: If set = {a, b}, then power set = {∅, {a}, {b}, {a, b}}.

Explanation

In indirect speech, "have to" becomes "had to" and "we" changes to "they" when referring to others.

The sentence is in the past reporting tense, so verb and pronoun shifts are necessary.

Explanation

تھڑا اٹھنا کا مطلب ہے سخت کانپنا یا شدید خوف یا سردی کی وجہ سے جسم میں کپکپی آنا۔

یہ اظہار عام طور پر جسمانی یا ذہنی حالت میں شدید ردعمل کو ظاہر کرنے کے لئے استعمال ہوتا ہے۔

Explanation

The poem 'A Green Cornfield' is written by Christina Rossetti.

Christina Rossetti was an English writer.

Christina Rossetti belonged to United Kingdom.

Explanation

If b² - 4ac < 0, the discriminant is negative, meaning the quadratic equation has complex (imaginary) roots.

These roots are conjugate pairs and unequal.