Explanation

• The oesophagus is a muscular tube that connects the pharynx (throat) to the stomach.
• Its main function is to transport food from the pharynx to the stomach through peristalsis (wave-like muscle contractions).

Explanation

Explanation

The mass of the proton is almost 1836 times heavier than that of an electron.

while

A neutron is 1842 times heavier than an electron.

Explanation

Explanation

Explanation

The K orbit, also known as the first electron shell.

• It can hold a maximum of 2 electrons.

The L orbit, also known as the second electron shell.

• It can hold a maximum of 8 electrons.

The M orbit, also known as the third electron shell.

• It can hold a maximum of 18 electrons.

Explanation

• Veins are the blood vessels that carry blood from other parts of the body back to the heart.
• They have one-way valves that prevent blood from flowing backwards and ensure it keeps moving towards the heart.

Explanation

• The female reproductive part of a flower is called the Pistil.

It consists of three parts:

1. Stigma (receives pollen grains)
2. Style (connects stigma to ovary)
3. Ovary (contains ovules/eggs)

The pistil is also sometimes referred to as the carpel, which is a modified leaf that forms the female reproductive organ.

Explanation

• The critical angle is the angle of incidence at which the angle of refraction is 90°, and beyond which total internal reflection occurs.
• This concept is crucial in understanding optical phenomena like fiber optics and prisms.

Explanation