N-Level Science 2

Question 1

What is the difference between a chemical change and a physical change?

Accepted Answer

A chemical change produces new substances and is usually irreversible, while a physical change does not produce new substances and is usually reversible

Answer

There is no difference

Answer

Physical changes are always permanent

Answer

Chemical changes only occur in labs

Question 2

What is the function of the kidneys in the human body?

Accepted Answer

To filter blood, remove waste products (urea), regulate water balance, and produce urine

Answer

To pump blood

Answer

To digest food

Answer

To produce hormones only

Question 3

What is the law of conservation of energy?

Accepted Answer

Energy cannot be created or destroyed, only converted from one form to another; the total energy in a closed system remains constant

Answer

Energy can be created from nothing

Answer

Energy always decreases over time

Answer

Energy can be destroyed but not created

Question 4

What causes the seasons in Singapore and other parts of the world?

Accepted Answer

The tilt of Earth's axis (23.5°) relative to its orbital plane around the Sun causes different regions to receive varying amounts of sunlight

Answer

The distance between Earth and the Sun changes

Answer

The Sun gets hotter and cooler

Answer

The Moon's gravity affects the seasons

Question 5

What is an ecosystem?

Accepted Answer

A community of living organisms interacting with each other and their non-living environment (e.g., air, water, soil) in a specific area

Answer

A type of plant

Answer

A single species of animal

Answer

A type of rock formation

Question 6

What is the pH scale used to measure?

Accepted Answer

The acidity or alkalinity of a substance, ranging from 0 (strongly acidic) to 14 (strongly alkaline), with 7 being neutral

Answer

Temperature

Answer

Weight

Answer

Electrical resistance