A genus is a group of closely related species. It’s the first part of the two-part system called binomial nomenclature, used to name living things.
Alkaline chemicals are basic — substances that produce hydroxide ions in solution.
Pi is the ratio of a circle’s circumference to its diameter. But some mathematicians say life would be easier if we used a different ratio instead.
Dinosaurs emerged between 243 and 233 million years ago. While some died out 66 million years ago, others are still with us — birds.
In clinical trials, scientists often test a drug or procedure against a placebo — a treatment that has no effect — to find out how well their new treatment works.
Acceleration is a change in velocity. That could mean a change in speed or in direction.
Radiation is the motion of energy through space as waves or particles.
Neurons are the foundational cells in the nervous system. They pass along and process information using electrical signals.
Scientists are still working out what counts as a hominid. Some say it’s just people and our extinct ancestors. Others say add more apes.
An egg or a sperm cell contains half of the normal genes an organism needs. They fuse together to form a new individual.
The state of the atmosphere in a specific place and time is weather. Over a long time, the weather conditions in an area will reveal its climate.
Planets have to orbit a star, be big enough to form a sphere and keep other objects out of their path around their star.