O-Level Combined Science 2

Question 1

What is an ionic bond?

Accepted Answer

The electrostatic attraction between oppositely charged ions formed by the transfer of electrons from a metal to a non-metal

Answer

Sharing of electrons between atoms

Answer

A bond between two non-metals

Answer

A weak intermolecular force

Question 2

What is the function of white blood cells in the immune system?

Accepted Answer

To defend the body against pathogens by producing antibodies, engulfing bacteria (phagocytosis), and producing antitoxins

Answer

To carry oxygen

Answer

To transport nutrients

Answer

To clot blood

Question 3

What is the relationship between speed, frequency, and wavelength of a wave?

Accepted Answer

v = f × λ, where v is speed, f is frequency, and λ is wavelength

Answer

v = f + λ

Answer

v = f / λ

Answer

v = f² × λ

Question 4

What is the difference between a series and parallel electrical circuit?

Accepted Answer

In series, components are connected end-to-end (same current); in parallel, components are connected across each other (same voltage)

Answer

They are identical

Answer

Series circuits have no resistance

Answer

Parallel circuits only have one path

Question 5

What is the greenhouse effect and how does it relate to climate change?

Accepted Answer

Greenhouse gases (CO₂, CH₄) trap heat radiation from Earth's surface, warming the atmosphere; excessive emissions intensify this effect causing global warming

Answer

Only occurs in greenhouses

Answer

It cools the Earth

Answer

It only affects polar regions

Question 6

What is the structure and function of the human heart?

Accepted Answer

A four-chambered muscular organ that pumps oxygenated blood to the body (left side) and deoxygenated blood to the lungs (right side)

Answer

A single-chambered pump

Answer

A three-chambered organ

Answer

A passive organ that does not pump