Q 01/05

Skin is the largest organ of the human body, making up roughly what share of body mass?

A) 16%

B) 22%

C) 30%

D) 45%

Answer · why

A) 16%

It weighs several kilograms and is the body's first line of defence.

Q 02/05

Roughly how much surface area does the skin of an average adult cover?

A) 3 to 4 square metres

B) 0.5 to 1 square metres

C) 1.5 to 2 square metres

D) 6 to 8 square metres

Answer · why

C) 1.5 to 2 square metres

That is about the size of a large bath towel or a small single bed.

Q 03/05

What are the three primary layers of human skin, from outside in?

A) Epidermis, dermis, hypodermis

B) Cuticle, cortex, medulla

C) Cornea, sclera, retina

D) Stratum, papilla, follicle

Answer · why

A) Epidermis, dermis, hypodermis

The hypodermis, or subcutaneous layer, is technically below the skin proper and holds much of the body's fat.

Q 04/05

The prefix 'epi' in epidermis comes from Greek and means what?

A) Underneath

B) Over or upon

C) Thin layer

D) Outer coat

Answer · why

B) Over or upon

The epidermis is the outermost layer and contains no blood vessels of its own.

Q 05/05

How is the epidermis, which contains no blood vessels, mostly nourished?

A) Lymph fluid seeping up from below

B) Oxygen diffusing in from the air

C) Oil spread by sebaceous glands

D) Sweat drawn back through the pores

Answer · why

B) Oxygen diffusing in from the air

Only its deepest cells get a small share from capillaries reaching up from below.