Q. How many TVs do the ordinary person have in their house?
A. In the United States, almost every single home (98 percent) has at least one TV set. A litle more than two-thirds have two TVs, and more than one-fourth have at least three. TVs are watched troughout the world. In Australia and France, there is one TV set for every two people. In brazil, there is one set for every 10 people. In Egypt, 11 people on average share one TV. In India one TV serves 48 people. And, in China, the average is one set for every 32 people. Japan may be tops - one for every 1.2 people!
Q. What is hair made of?
A. Hair is made up of dead cells filled with keratin. Keratin is a protein, and it's what fingernails are made of as well. Even though a strand of hair is very small in diameter, it has several layers, the outer cuticle, central medulla and cortex. The cuticle is made of several layers of cells. The medulla is the spongy but partly hollow core. The cortex is made up of long thin fibers. the root of a hair is lodged in the skin. The root is inside the bulb, and this is where the keratin comes from. The color of hair is decided by melanin in the hair shaft.
Q. How come the pupils of cats' eyes look like slits?
A. The pupil is a hole in the iris, which is the colored part of the eye. The pupil is formed by a muscle that tightens or loosens, depending on how much light the eye needs in order to see well. In bright light, the pupil can be smaller. In dim light, the pupil needs to be big, to let lots of light reach inside the eye.
Round pupils are formed by a muscle that makes a circle, like your lips do when you drink through a straw.
But the muscles in a cat's eye are different. They're shaped more like lines than circles, so in bright light, they cause the pupil til narrow into a slit shape instead of a dot.
It's mostly domestic cats - the kind that are pets - that have pupils shaped like vertical slits. Wild cats tend to have round pupils.
Some other animals also have odd-shaped pupils. Stingrays have a U-shaped pupil, for example, and horses and ferrets have a horizinatal oval or slit-like pupil.