But fortunately for most of us, the immune system is constantly on duty to battle germs that could make us ill. The following discussion questions and activities will help your students learn about how the immune system protects them from germs and illness.
Elephants however, go through six sets of 9lb teeth during their lifetimes, with new teeth growing in to replace old ones that have worn out. An elephants starts with two front teeth that fall out after about a year and are replaced by a set of tusks.
Tusks are an elephant's incisor teeth and are the only incisors an elephant has. They are used for defense, digging for water and food, and lifting things. The tusks present at birth are milk teeth, which fall out after a year when they are about 12 inches (5 centimeters) long.