Explanation

Chromosomes are made up of:

• Nucleic acid (DNA or RNA)
• Proteins (histones and non-histone proteins)

A chromosome is made up of proteins and DNA organized into genes.

Each cell normally contains 23 pairs of chromosomes.

Explanation

• Carbon dioxide (CO2) is a major greenhouse gas.
• It responsible for about 65% of the Earth's greenhouse effect.

Explanation

• Fission is the splitting of a nucleus that releases free neutrons and lighter nuclei.
• The fission of heavy elements is highly exothermic which releases about 200 million eV compared to burning coal which only gives a few eV.

Explanation

The rod cells of the retina are responsible for vision in dim light or at night (scotopic vision),

Providing black and white, low-resolution vision, and contributing to peripheral vision.

They are more numerous and more sensitive to light than cone cells, but they cannot detect color or fine details. 

Explanation

A device that opposes the flow of electrons in electronic circuits is called a resistor.

It is a passive two-terminal component used to reduce current flow, divide voltage, and perform other functions by creating resistance.

Resistance is measured in ohms (Omega). 

Explanation

The pressure of a gas in a container is affected by:

• Temperature (increases with temperature)
• Volume (decreases with increasing volume)
• Density of gas (increases with density)

However, the material of the container does not directly affect the pressure of the gas.

Explanation

A refracting telescope has two lenses:

1. A primary lens (objective) that collects and focuses light.
2. A secondary lens (eyepiece) that magnifies the focused light to form an image.

Explanation

• In a mercury thermometer, the mercury in the bulb expands and rises in the tube, which has a linear scale ranging from 94°F to 108°F.
• This specific range is commonly used for medical thermometers to measure human body temperature.

Explanation

• Atmospheric pressure is a scalar quantity that acts equally in all directions, pressing on surfaces from all sides.
• This is why a balloon expands in all directions when inflated, and why a submarine is squeezed from all sides by the surrounding water pressure.

Explanation

• Pollution is the introduction of harmful or poisonous substances into the environment, causing damage to the air, water, and land.
• This can have harmful effects on human health, wildlife, and the ecosystem as a whole.