Explanation

The distance between the optical center and the principal focus is called the focal length of the lens.

while

A negative focal length indicates that the system diverges light.

Explanation

DNA is the fundamental molecule that carries genetic information, forming the basis of heredity alongside chromosomes and genes.

It is the hereditary material in almost all organisms, encoding the instructions for building proteins and other important molecules.

Explanation

A geostationary satellite orbits the Earth once every 24 hours, matching the Earth's rotation.

This keeps it fixed over the same spot on the equator, making it ideal for communication and weather monitoring.

Explanation

• The male reproductive part of a flower is called the Stamen.

It consists of two parts:

1. Anther (produces pollen grains)
2. Filament (supports the anther)

Explanation

Snails are mollusks, belonging to the phylum Mollusca.

They typically have a soft body and, in many cases, an external shell.

Explanation

The average weight of an adult human brain is about 1300 to 1400 grams.

It makes up around 2% of the total body weight but consumes about 20% of the body's energy.

Explanation

Explanation

Materials are classified based on how they conduct heat.

- Conductors: Allow heat to pass through easily (e.g., metals like copper, iron).

- Insulators: Do not allow heat to flow through easily.

- Examples of insulators: Wood, plastic, rubber, glass.

- Used in cooking handles, thermal flasks, and electrical wire coatings.

Explanation

In the Fahrenheit scale:

• The freezing point of water is 32°F
• The boiling point of water is 212°F

Explanation

Robert Hooke, a 17th-century philosopher and scientist.

He was the first to use the word "cell" to describe a basic unit of life.