For 2 billion years, bacteria were the only creatures on Earth. Long before the dinosaurs, a special type of bacteria slowly increased the level of oxygen in the Earth’s air to 20 percent. Without this oxygen other plants and animals could not have evolved, including us.
Carol is a botanist, which means she studies plants. Carol says, “Nature is a place to have fun and learn new things at the same time. Just pick a little spot and watch it for a while. Soon you will discover hundreds of little things going on in just that one little spot. Multiply that by thousands and thousands of little spots, and wow!”