N-Level Combined Science 4

Question 1

What is meant by 'adaptation' in biology?

Accepted Answer

A feature of an organism that helps it survive and reproduce in its environment

Answer

An adaptation is a feature (structural, behavioural, or physiological) that improves an organism's chances of survival and reproduction in its particular environment.

Question 2

What type of reaction produces a precipitate?

Accepted Answer

A reaction where an insoluble solid forms from mixing two solutions

Answer

A precipitate is an insoluble solid formed when two solutions are mixed. For example, mixing lead nitrate and sodium iodide solutions produces a yellow precipitate of lead iodide.

Question 3

What is the speed of light in a vacuum?

Accepted Answer

3 × 10⁸ m/s

Answer

The speed of light in a vacuum is approximately 3 × 10⁸ m/s (300,000,000 m/s or 300,000 km/s).

Question 4

In photosynthesis, what does the plant produce?

Accepted Answer

Oxygen and glucose

Answer

Photosynthesis: CO₂ + H₂O + light energy → glucose + O₂. Plants produce glucose (food) and oxygen as a by-product.

Question 5

What is the difference between mass and weight?

Accepted Answer

Mass is the amount of matter in an object (kg); weight is the gravitational force on an object (N)

Answer

Mass is the amount of matter in an object, measured in kg — it stays constant anywhere. Weight is the gravitational force on an object (W = mg), measured in Newtons, and varies with gravity.

GCE N-Level Practice Test

GCE N-Level Practice Test

N-Level Combined Science 4