Q 01/05

Roughly how many neurons does the human brain contain?

A) 86 billion

B) 860 billion

C) 8.6 trillion

D) 8.6 billion

Answer · why

A) 86 billion

There are about as many non-neuronal cells again, mostly glia; the cerebellum alone holds most of the neurons.

Q 02/05

About what share of the body's energy does the brain consume?

A) 10%

B) 20%

C) 15%

D) 5%

Answer · why

B) 20%

That is more than any other organ, from roughly 2% of body weight; it also takes about a quarter of the body's glucose.

Q 03/05

The adult human brain weighs on average about how much?

A) 3.0–3.5 kg

B) 1.8–2.0 kg

C) 1.2–1.4 kg

D) 2.0–2.5 kg

Answer · why

C) 1.2–1.4 kg

Men's brains average about 1370 g and women's about 1200 g, with wide individual variation.

Q 04/05

What everyday food is the living brain's consistency compared to?

A) Hard cheese

B) Cold butter

C) Ripe banana

D) Soft tofu

Answer · why

D) Soft tofu

That softness is why the brain floats in cerebrospinal fluid inside the skull rather than resting on bone.

Q 05/05

Which three main parts make up the human brain?

A) Cerebrum, brainstem and cerebellum

B) Cortex, thalamus and spine

C) Left lobe, right lobe and bridge

D) Grey matter, white matter and fluid

Answer · why

A) Cerebrum, brainstem and cerebellum

The cerebrum is by far the largest; the brainstem links it to the spinal cord and the cerebellum sits behind.