Earth and Nature
1.
Did you knowthat bacteria live everywhere?
They live in the soil and the water. They live in plants and every living thing. They e____1____live on and in the bodies of animals and people.
Can you find and p____2____ at the bacteria on your body now？
No way! You can’t see these tiny single-celled living things without a microscope.
However, you know they are there. Sometimes, bacteria in the water or soil can be h____3____ they cause diseases in people, plants, and animals. In h_____4____, bacteria can cause sicknesses like ear infections. In plants, bacteria work as decomposers. However, bacteria can be h ____5___ too. Some scientists h____6____ bacteria in the environment to do good things. For example, they put bacteria into polluted environments to get r___7___ of industrial waste. And bacteria are used to clean up sewage and oil spills.
1. even 2.point 3.harmful 4.humans 5.helpful 6.help 7.rid
2.
All sounds make waves.
When you hear your friend’s voice, these sound waves go into your e____1___ and you can identify your friend’s voice.
U____2____, we cannot see sound waves but we can if we use some simple m____3____. Put a piece of tissue close to your l___4____ and speak. Then you can see the tissue moving when you speak. If you speak loudly, the tissue moves more, and if you speak softly, the tissue moves less. This happens because the sound waves have viration.
In s____5____, there are names for different sound waves. When the sound viration is s____6___ , we call this a low-pitch sound. But when the sound vibration is fast, we call this a high-pitch sound. Pitch d____7____ how high or low a sound is. When the sound has less energy, we say it has a soft volume. But when the sound has more energy, we say it has a loud volume. Volume is a measure of how loud or soft a sound is. 1.ears 2.Usually 3.materials 4.lips 5.science 6.slow 7.describes