Q 01/05

What do house dust mites mostly eat?

A) Loose carpet fibres

B) Dropped sugar crumbs

C) Shed pet hair

D) Flakes of human skin

Answer · why

D) Flakes of human skin

Flakes of human skin work their way deep into mattresses, pillows and sofas, so that is where the mites gather; most people meet them while asleep in ...

Q 02/05

House dust mites never bite, so what sets off most dust-mite allergies?

A) A toxin in their saliva

B) Proteins in their droppings

C) Eggs laid under the skin

D) Mould carried on their legs

Answer · why

B) Proteins in their droppings

Proteins in their droppings, mostly leftover digestive enzymes, cause the reaction once breathed in; one national survey found the allergen in the bed...

Q 03/05

Demodex mites are eight-legged relatives of spiders that spend their lives where on the human body?

A) Under the fingernails

B) Between the toes

C) In facial hair follicles

D) Inside the belly button

Answer · why

C) In facial hair follicles

In facial hair follicles, tucked out of sight: researchers could see the mites on only 14% of volunteers, yet DNA tests found them on every adult they...

Q 04/05

What is earwax mostly made of?

A) Dried-up sweat

B) Dried-up mucus

C) Trapped dust

D) Shed skin cells

Answer · why

D) Shed skin cells

Shed skin cells, rich in the protein keratin, make up most of it; the ear canal's skin creeps outward like a conveyor belt, and chewing or talking hel...

Q 05/05

Human earwax comes in which two genetically determined types?

A) Sweet and sour

B) Light and dark

C) Hard and soft

D) Wet and dry

Answer · why

D) Wet and dry

Wet and dry earwax are set by a single letter of DNA in one gene; the dry version, common in East Asia, also leaves people with far less armpit odour.