Daily challenge · 1 October 2026
Science and nature
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Question 1
Which part of a plant usually takes up water from the soil?
- A Roots
- B Flowers
- C Seeds
- D Leaves
Roots absorb water and dissolved minerals from the soil.
Question 2
What word describes animals that are most active around dawn and dusk?
- A Nocturnal
- B Crepuscular
- C Diurnal
- D Fossorial
Crepuscular animals are especially active during twilight periods.
Question 3
In which layer of Earth's atmosphere is most of the ozone layer found?
- A Troposphere
- B Mesosphere
- C Stratosphere
- D Thermosphere
Most atmospheric ozone is concentrated in the stratosphere.
Question 4
What is the SI unit of electrical resistance?
- A Watt
- B Volt
- C Ampere
- D Ohm
Electrical resistance is measured in ohms, symbolized by Ω.
Question 5
What type of plate boundary occurs where two tectonic plates slide horizontally past one another?
- A Convergent
- B Transform
- C Divergent
- D Subduction
At a transform boundary, plates move sideways relative to each other.
Question 6
Which mammals are capable of powered, sustained flight?
- A Bats
- B Flying squirrels
- C Colugos
- D Sugar gliders
Bats are the only mammals capable of powered flight; the other animals glide.
Question 7
Who discovered the first known radio pulsar signal while working as a graduate student?
- A Cecilia Payne-Gaposchkin
- B Vera Rubin
- C Jocelyn Bell Burnell
- D Henrietta Swan Leavitt
Jocelyn Bell Burnell identified the unusual repeating radio signal in 1967.
Question 8
Which lake holds about one-fifth of the world's unfrozen surface freshwater?
- A Lake Victoria
- B Lake Baikal
- C Lake Tanganyika
- D Lake Superior
Lake Baikal contains roughly 20% of the world's unfrozen surface freshwater.
Question 9
Which North American frog can survive having much of its body freeze during winter?
- A American bullfrog
- B Wood frog
- C Green tree frog
- D American toad
Wood frogs tolerate extensive freezing of body fluids and recover when they thaw.
Final question
What is the name of the mineral thought to be the most abundant in Earth's lower mantle?
- A Olivine
- B Bridgmanite
- C Quartz
- D Feldspar
Bridgmanite, a magnesium iron silicate with a perovskite structure, is inferred to dominate the lower mantle.