Q 01/05

Which planet is the hottest in the Solar System?

A) Venus

B) Jupiter

C) Mercury

D) Mars

Answer · why

A) Venus

It is not the closest to the Sun, but its thick carbon-dioxide atmosphere traps heat until the surface reaches about 464 °C.

Q 02/05

How many hearts does an octopus have?

A) Four

B) Three

C) One

D) Two

Answer · why

B) Three

One main heart pumps blood round the body and two smaller ones pump it through the gills; the main one stops when the octopus swims, so it prefers to ...

Q 03/05

What is the smallest bone in the human body?

A) The tail bone

B) The nose bone

C) The stapes, in the ear

D) The pinky toe bone

Answer · why

C) The stapes, in the ear

It is shaped like a stirrup and passes sound vibrations into the inner ear.

Q 04/05

Roughly how many bones does an adult human have?

A) 186

B) 156

C) 176

D) 206

Answer · why

D) 206

Babies are born with about 270, but many fuse together as they grow.

Q 05/05

Which is the largest desert in the world?

A) Antarctica

B) The Gobi

C) The Sahara

D) The Arabian Desert

Answer · why

A) Antarctica

A desert is defined by how little rain or snow falls, not by heat, and Antarctica gets very little. The Sahara is only the largest hot desert.