How do people breathe in and out?

          We usually don’t have to think much about our breathing because our brain controls it automatically. When you have a lot of carbon dioxide the waste gas produced by body processes in our blood, our brain gets the message and tells our lungs to exhale and get rid of it. This action then causes us to inhale, drawing in air that eventually delivers oxygen to every cell in our body. This carefully regulated exhaling and inhaling takes place about 10 to 14 times each minute when we are breathing calmly.

What is AIDS?

AIDS stands for: Acquired Immune Deficiency Syndrome

AIDS is a medical condition. A person is diagnosed with AIDS when their immune system is too weak to fight off infections.Since AIDS was first identified in the early 1980s, an unprecedented number of people have been affected by the global AIDS epidemic. Today, there are an estimated 33.3 million people living with HIV and AIDS worldwide.

Why Is the Sky Blue?

Why Is the Sky Blue?

 The sun emits light that travels through space toward Earth because space is a vacuum. The light remains largely undisturbed until it nears the Earth, whose atmosphere is made up of a mixture of gas molecules (mainly oxygen and nitrogen) and other materials. The closer you get to the Earth, the thicker the atmosphere. Light from the sun appears white but is in fact a combination of colors, and the range of these colors that are visible to the human eye from red to violet, by way of orange, yellow, green, blue and indigo is shown when light is passed through a prism These different colors have different wavelengths and energies, with violet having the shortest wavelength and highest energy and red having the longest wavelength and lowest energy.