Explanation

Antibodies are proteins produced by the immune system to neutralize or destroy antigens (disease-causing agents).

They are a key part of the body’s defense mechanism against pathogens like bacteria and viruses.

Explanation

Explanation

Frogs can breathe through their skin, lungs, and lining of the mouth, especially in water where cutaneous respiration is key.

This ability helps them absorb oxygen directly from their environment.

Earthworms and amphibians, such as frogs, breathe through their skin. 

Explanation

Tuberculosis (TB) is a bacterial infection caused by Mycobacterium tuberculosis, and its symptoms include:

• Fever
• Chest pain
• Coughing up blood or phlegm
• Sweating at night
• Fatigue
• Weight loss (not weight gain)

Explanation

Eukaryotic cells have a well-defined nucleus enclosed by a nuclear membrane.

Prokaryotic cells lack a nucleus — their DNA floats freely in the cytoplasm.

This is the main difference between the two.

Explanation

Explanation

• Argon (Ar) is a noble gas that is not typically associated with acid rain.

Acid rain is caused by the presence of pollutants in the air, such as:

• Sulfur dioxide (SO2)
• Nitrogen oxides (NOx)
• Oxygen (O2) plays a role in the formation of acid rain, as it reacts with SO2 and NOx to form acidic compounds.

Explanation

Diamond is a crystalline form of carbon where atoms are arranged in a regular, repeating lattice structure.

This structure gives diamond its hardness and brilliance, unlike coke or charcoal, which are amorphous.

Explanation

Diffusion is the movement of particles from high to low concentration and occurs rapidly in gases, slowly in liquids, but is negligible in solids.

In solids, particles are tightly packed and cannot move freely, so diffusion does not occur significantly.

Explanation

A covalent bond forms when two atoms share one or more pairs of electrons.

This type of bonding typically occurs between non-metal atoms to achieve stable electron configurations.