Problem: When you get sick, your body springs to action. Your body starts to fight the illness. Thats why you want to eat right and get plenty of sleep. You need a strong immune system to fight off illness. Plants dont have an immune system. That does not mean they do not get sick. Plants are affected by disease just like us. Typically, their first line of defense is the death of part of the plant. This prevents the infection from spreading. Many plants also produce special chemicals to fight disease. For example, willow trees produce a chemical to kill the bacteria. The same compound is used in many acne products. You can see a picture of a willow tree in Figure Plants may be smarter than we think. No, they cannot talk to each other. They may be able to send messages, though.

Question: "What do humans have that plants don't have?"

Answer: "Germs"

OPTIONS:
- no
- yes
Answer: no

Problem: Surely, you have noticed the tall poles along the roadside. Do you know what is on top of those poles? Thats right, wires that carry electric current. These wires carry electric current to your home. But what is electric current? Electric current is actually the flow of electrons. You may recall, an electron is the outer-most particle in an atom. They have a negative charge. Electricity is the continuous flow of these particles. Electrons are able to move through wires. Their speed can even be measured. The SI unit for electric current (or speed) is the ampere (A). Ampere is often shortened to amp. Electric current may flow in just one direction, or it may keep reversing direction. Direct current (DC) flows in only one direction. Direct current is what is used in devices like flashlights. Alternating current (AC) flows in two directions. This is the type of current that flows into your home through wires.

Question: "Do electrons have a positive or negative charge?"

Answer: "Negative Only"

OPTIONS:
- no
- yes
Answer: yes

Problem: The world can be divided into three climate zones. The first climate zone is the polar zone. As it sounds, the polar zone is near earths poles. The polar zone has very long and cold winters. Brrr!!!! Near the equator is the tropical zone. The tropical zone is known for being hot and wet. Between these two zones is the temperate zone. Temperatures there tend to be mild. Its not too hot and not too cold. You might expect places near the equator to be hot and wet. Thats not always the case. Sometimes there are other factors at work. These factors can affect the local climate type or a region. Oceans and mountain ranges can have a major impact. They can greatly influence the climate of an area. Many factors influence an areas climate.

Question: "What are some characteristics of the first climate zone?"

Answer: "Long and cold winters"

OPTIONS:
- no
- yes
Answer:
yes