Explanation

 Angle in radians (θ) = Arc Length / Radius  

θ = 4 m / 2 m = 2 radians

So, the angle made at the center is 2 rad

Explanation

One up quark and two down quarks, when combined, make a neutron. 

More specifically:

A proton consists of two up quarks and one down quark (uud). 

A neutron consists of one up quark and two down quarks (udd). 

An electron and a positron are elementary particles, not composed of quarks. 

Explanation

 To calculate the bond order of O2²⁻, we need to construct a molecular orbital diagram.

The molecule has 18 electrons (12 from oxygen atoms and 6 from the negative charge).

These electrons are filled into the orbitals, starting from the lowest energy level. 

Explanation

 p24:

This protein is part of the Gag protein complex, which is responsible for forming the viral core.

The matrix is the layer surrounding the viral core, and p24 is the primary structural component of this matrix. 

gp120 and gp41:

These are glycoproteins on the surface of the HIV envelope.

They are involved in viral attachment to and entry into host cells, but not the formation of the matrix. 

Explanation

 The sex of a baby is determined by the sperm that fertilizes the egg.

If the sperm carries a Y chromosome, the baby will be a son.

If the sperm carries an X chromosome, the baby will be a daughter.

Since the chances of receiving a Y or an X chromosome are roughly equal, the probability of having a son or a daughter is approximately 50/50, or 1:1. 

Explanation

Mycoplasma is a type of bacteria, not a virus.

It lacks a cell wall, which makes it resistant to certain antibiotics.

Bacteria are capable of independent replication, unlike viruses which need a host cell. 

SARS, FIV, and HIV are all viruses:

SARS stands for Severe Acute Respiratory Syndrome,

FIV for Feline Immunodeficiency Virus,

HIV for Human Immunodeficiency Virus.

These are all viruses that infect specific hosts and require a host cell to replicate their genetic material. 

Explanation

The mass of a nucleus is always less than the sum of the masses of its constituent nucleons.

This difference in mass is known as the "mass defect".

When nucleons come together to form a nucleus, they release energy in the form of binding energy.

According to Einstein's famous equation E=mc², this energy released corresponds to a decrease in mass. 

Explanation

Coal can be converted to petroleum through the Fischer-Tropsch process. 

The Fischer-Tropsch process is a series of chemical reactions

That converts carbon monoxide and hydrogen (syngas) into liquid hydrocarbons, which can be used as a substitute for petroleum. 

Explanation

The organelle responsible for the breakdown of fatty acids and detoxification of alcohol in the liver is Peroxisome. 

Peroxisomes are small organelles that contain enzymes capable of breaking down fatty acids and detoxifying harmful substances like alcohol. 

Explanation

They can be reshaped – False.

While cartilage is flexible, it does not permanently change shape without surgical intervention or long-term external force (like in orthodontics or ear reshaping).

It’s not inherently reshaping like soft tissues.