What is the chemical formula for water?
H₂O Two hydrogen atoms bonded to one oxygen atom at roughly a 104.5° angle.
How many bones does a typical adult human skeleton contain?
206 Babies are born with around 270 bones; many fuse during growth to reach 206 in adulthood.
What is the atomic number of carbon?
6 Atomic number equals the number of protons; carbon has 6.
Which organ of the human body produces insulin?
The pancreas Insulin is produced by beta cells within the islets of Langerhans in the pancreas.
What is the largest animal that has ever lived?
The blue whale Blue whales can reach 30 m long and 190 tonnes — larger than any known dinosaur.
What is the scientific study of earthquakes called?
Seismology Seismologists use seismographs to record ground motion and infer what is happening beneath our feet.
Which gas do plants release as a by-product of photosynthesis?
Oxygen Plants take in CO₂ and water and produce glucose plus O₂ using sunlight energy.
How many hearts does an octopus have?
Three Two branchial hearts pump blood through the gills; one systemic heart pumps it around the body.
Which subatomic particle has no electric charge?
The neutron Protons are positive, electrons negative; neutrons are electrically neutral.
What is the chemical symbol for potassium?
K K comes from Latin "kalium" (from Arabic "al-qaliy", meaning calcined ashes).
Which blood type is considered the universal donor?
O negative O-negative red cells have no A, B or Rh antigens, so they can be given to anyone in an emergency.
What is the scientific study of fossils called?
Palaeontology Palaeontologists study prehistoric life through fossils — bones, shells, impressions and trace fossils.
Which element is the most abundant in Earth's crust by mass?
Oxygen Oxygen makes up about 46% of the crust by mass — mostly locked inside silicate rocks.
What is the SI unit of force?
The newton One newton is the force needed to give 1 kg an acceleration of 1 m/s². Named after Sir Isaac Newton.
What is the smallest unit of an element that retains the element's properties?
The atom Atoms consist of a nucleus (protons + neutrons) surrounded by electrons. Molecules are groups of atoms.
Who is credited with the theory of evolution by natural selection?
Charles Darwin Darwin published "On the Origin of Species" in 1859. Wallace co-developed the theory independently.
Approximately what is the boiling point of liquid nitrogen in degrees Celsius?
-196 °C Liquid nitrogen boils at 77 K (-196 °C / -321 °F); widely used for cryopreservation.
What is the most abundant element in the universe?
Hydrogen Hydrogen makes up roughly 75% of all normal matter in the universe; helium is second at 24%.
What is the smallest bone in the human body?
The stapes The stapes (stirrup) in the middle ear measures just 2.5-3 mm in length.
How many pairs of chromosomes does a typical human cell contain?
23 23 pairs = 46 chromosomes total (22 autosomal pairs plus one pair of sex chromosomes).
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