Daily challenge · 24 September 2026
Science and nature
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Question 1
Which of these animals is a mammal?
- A Dolphin
- B Trout
- C Frog
- D Tortoise
Dolphins are mammals: they breathe air and nurse their young.
Question 2
Which gas do plants take in from the air during photosynthesis?
- A Oxygen
- B Carbon dioxide
- C Nitrogen
- D Helium
Plants use carbon dioxide, along with water and light, to make sugars.
Question 3
Which is the largest desert on Earth by area?
- A The Sahara
- B The Gobi
- C The Antarctic
- D The Arabian Desert
Antarctica is a polar desert because it receives very little precipitation.
Question 4
The Svalbard Global Seed Vault is on which island?
- A Spitsbergen
- B Madagascar
- C Baffin Island
- D Tasmania
The vault is near Longyearbyen on Spitsbergen, part of Norway’s Svalbard archipelago.
Question 5
Who coined the phrase “survival of the fittest”?
- A Charles Darwin
- B Alfred Russel Wallace
- C Herbert Spencer
- D Thomas Huxley
Herbert Spencer introduced the phrase; Darwin later adopted it in a subsequent edition of On the Origin of Species.
Question 6
Which planet takes longer to rotate once on its axis than to orbit the Sun?
- A Mars
- B Venus
- C Jupiter
- D Mercury
Venus rotates once in about 243 Earth days but orbits the Sun in about 225 Earth days.
Question 7
The Large Hadron Collider’s underground ring runs beneath the border of which two countries?
- A France and Switzerland
- B Germany and Austria
- C Italy and Slovenia
- D Belgium and the Netherlands
The collider is near Geneva, and its ring extends beneath both France and Switzerland.
Question 8
What is the name of the deepest known point in the ocean?
- A Puerto Rico Trench
- B Horizon Deep
- C Challenger Deep
- D Milwaukee Deep
Challenger Deep lies in the Mariana Trench in the western Pacific Ocean.
Question 9
An unusual concentration of which element at the Cretaceous–Paleogene boundary helped support the idea that an asteroid impact caused the mass extinction?
- A Iridium
- B Lithium
- C Aluminium
- D Calcium
Iridium is rare in Earth’s crust but more abundant in many asteroids; its presence in the boundary layer was important evidence for the impact hypothesis.
Final question
The exoplanet 51 Pegasi b, announced in 1995 as the first planet found orbiting a Sun-like star, was detected using which technique?
- A Transit photometry
- B Radial-velocity measurements
- C Gravitational microlensing
- D Direct imaging
Its discovery used the radial-velocity method, measuring the star’s small back-and-forth motion caused by the planet’s gravity.