Q 01/05

Twins that develop from a single fertilized egg that splits into two embryos are called what?

A) Dizygotic

B) Monozygotic

C) Heterozygous

D) Polyzygotic

Answer · why

B) Monozygotic

Monozygotic twins are the 'identical' kind; dizygotic twins each grow from a separate egg. The Greek roots literally mean 'one yolk' versus 'two yolks...

Q 02/05

Roughly what share of human births are twins?

A) About 1 in 30

B) About 1 in 90

C) About 1 in 400

D) About 1 in 1,000

Answer · why

B) About 1 in 90

That works out to about 1.1 percent of births. Identical twins are much rarer, at roughly 3 to 4 per 1,000 births.

Q 03/05

The Yoruba people of West Africa have the world's highest twinning rate. Roughly how many twin sets are born per 1,000 live births there?

A) About 10

B) About 20

C) About 30

D) About 45

Answer · why

D) About 45

That is 90 to 100 twins per 1,000 births, several times the global average. Twins hold a special place in Yoruba religion, where they are called Ibeji...

Q 04/05

A 2011 global study found the highest national twinning rate, 27.9 per 1,000 births, in which country?

A) Ghana

B) Brazil

C) Benin

D) Ireland

Answer · why

C) Benin

The same study found the lowest rates in South and Southeast Asia and Latin America, where twinning runs below 9 per 1,000.

Q 05/05

Igbo-Ora, nicknamed the 'Twin Capital of the World,' is a town in which country?

A) Nigeria

B) Kenya

C) Cameroon

D) Senegal

Answer · why

A) Nigeria

Locals often credit the diet, and researchers have looked at a chemical found in yam peelings, though nothing has been proven.