Q 01/05

Humans have four types of photoreceptor cell. How many does a mantis shrimp have?

A) Exactly 10

B) Between 12 and 16

C) Between 6 and 8

D) More than 30

Answer · why

B) Between 12 and 16

Their clubs also strike with an acceleration of about 10,400 g, fast enough to boil the water around them into cavitation bubbles.

Q 02/05

To what temperature does the air around a lightning flash heat?

A) About 12,000 °C

B) About 5,500 °C

C) About 30,000 °C

D) About 100,000 °C

Answer · why

C) About 30,000 °C

Earth sees roughly 44 flashes every second, close to 1.4 billion a year.

Q 03/05

Tardigrades in their dormant state have survived temperatures as low as what?

A) −196 °C

B) −272 °C

C) −150 °C

D) −80 °C

Answer · why

B) −272 °C

That is a single degree above absolute zero; they have also survived the vacuum and radiation of open space.

Q 04/05

Who first described tardigrades in 1773, calling them "little water bear"?

A) Lazzaro Spallanzani

B) Carl Linnaeus

C) Antonie van Leeuwenhoek

D) Johann August Ephraim Goeze

Answer · why

D) Johann August Ephraim Goeze

Spallanzani supplied the name Tardigrada, meaning slow walkers, three years later.

Q 05/05

How old was Methuselah, the bristlecone pine in California's White Mountains, in 2025?

A) 3,210 years

B) 4,858 years

C) 1,900 years

D) 2,750 years

Answer · why

B) 4,858 years

At 4,858 years in 2025 it is the oldest known living non-clonal organism, already ancient when Stonehenge was finished.