Explanation

I have never known him for a long time.

میں اسے ایک عرصے سے کبھی نہیں جانتا تھا۔

"Have never known" is the correct present perfect tense.

It indicating that up until now, the speaker has never known the person.

Explanation

The following table provides the botanical names for a variety of familiar plants: 

Explanation

Angular acceleration is produced by torque.

Torque is the rotational equivalent of force.

And just as force causes linear acceleration, torque causes angular acceleration. 

Explanation

Orbitals that have the same energy level are called degenerate orbitals.

This concept is important in understanding electron behavior and how they fill atomic orbitals, following principles like the Aufbau principle and Hund's rule.

For example, in a hydrogen atom, all orbitals with the same principal quantum number (n) are degenerate. 

Explanation

Monosaccharides are the building blocks of disaccharides (such as sucrose, lactose, and maltose) and polysaccharides (such as cellulose and starch).

A glycosidic bond is a covalent bond that connects two monosaccharides to form a disaccharide or polysaccharide. 

Explanation

Explanation

Molarity is calculated by dividing the number of moles of solute by the volume of solution in liters. 

Therefore, the molarity of pure water is approximately 55.56 moles/L, or approximately 55.5 M. 

Explanation

Coralline red algae are the type of algae that play a role in building coral reefs, along with coral animals.

These algae secrete and deposit calcium carbonate.

It helps to cement the reef structure together.

Explanation

Since fluorine is more electronegative, its oxidation state is -1.

The molecule OF2 has zero overall charge:

O + 2F = 0

x + 2(-1) = 0

x - 2 = 0

x = +2

Explanation

Kinetic energy (KE) is expressed as: 

KE = 1/2 * mv² 

Where: m = mass (dimensions: M¹), v = velocity (dimensions: L¹T⁻¹), and v² = (L¹T⁻¹)² = L²T⁻². 

Therefore, the dimensions of KE are: 

KE = M¹ * (L²T⁻²) = M¹L²T⁻²