Nicotine is an addictive substance found in tobacco plants. It's what makes it so difficult to quit smoking or vaping.
In chemistry, this attachment between atoms forms because of the power of attraction. Chemical bonds make up every solid object on Earth.
Pollen is a mass of tiny reproductive cells. These grains combine with egg cells to form seeds — but on the way, they can make some people miserable.
Metals are substances that can be elements, alloys or compounds. They all conduct heat and electricity and can be formed into different shapes.
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.