Red cells contain a special protein called hemoglobin, which helps carry oxygen from the lungs to the rest of the body and then returns carbon dioxide from the body to the lungs so it can be exhaled.

The opposite of sublimation is "deposition", where water vapor changes directly into ice—such a snowflakes and frost. It is not easy to actually see sublimation occurring, at least not with ice. One way to see the results of sublimation is to hang a wet shirt outside on a below-freezing day.

Sir Isaac Newton was born especially tiny but grew into a massive intellect and still looms large, thanks to his findings on gravity, light, motion, mathematics, and more.

Gold's chemical symbol AU is derived from the Latin word aurum, meaning gold. Some claim that the word aurum also means shining dawn due to its etymological ties to the word aurora, meaning dawn. The word gold comes from the old English word for yellow, geolu, which was derived from the Germanic word gulþa.

Gamma Rays- Gamma Rays-have the smallest wavelengths and the most energy of any other wave in the electromagnetic spectrum. These waves are generated by radioactive atoms and in nuclear explosions. Gamma-rays can kill living cells, a fact which medicine uses to its advantage, using gamma-rays to kill cancer cells

They are caused by the gravitational forces exerted on the earth by the moon, and to a lesser extent, the sun. When the highest point in the wave, or the crest, reaches a coast, the coast experiences a high tide. When the lowest point, or the trough, reaches a coast, the coast experiences a low tide.

Mars is sometimes called the Red Planet. It's red because of rusty iron in the ground. Like Earth, Mars has seasons, polar ice caps, volcanoes, canyons, and weather.

Photosynthesis is the process by which plants use sunlight, water, and carbon dioxide to create oxygen and energy in the form of sugar.

Atoms are the smallest units of matter that have all the characteristics of an element. Atoms combine to form molecules. Atoms are composed of smaller particles known as protons, neutrons, and electrons.

Chlorophyll is responsible for the green color of many plants and algae. Seen through a microscope, chlorophyll is concentrated within organisms in structures called chloroplasts – shown here grouped inside plant cells.