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Farming allowed Native American people to grow more food. However, they had to stay in one place to tend their gardens. As a result, people began living in larger, permanent villages. Populations grew and developed more complicated governments. Because they lived in large groups, people could also develop more specific skills.

• Native Americans were farmers.

• Native Americans moved often.

• Farming had many effects for Native American people.

There are about 60 million cells in your body. There are several hundred types of cells, each with its own job. Nerve cells send signals through your body. Sensory cells help you see, hear, touch, taste, and smell the world around you. Blood cells carry oxygen and fight infections. Without these many cells, your body would not work.

• The cells in your body have many different functions

• Nerve cells help you feel pain.

• Blood cells carry oxygen and fight infections.

While erupting volcanoes are beautiful to watch, they can disrupt air travel. For example, a 2001 eruption of Mount Etna sprayed ash high into the atmosphere and closed nearby airports. The grainy ash covered the land and made runways dangerous. The wind also carried the ash and made it difficult to avoid in the air.

• Ash covered land makes runways dangerous.

• Volcanic eruptions can cause trouble for air traffic.

• Erupting volcanoes are beautiful to watch.

Tomatoes are a great addition to your garden. They come in many types, from tiny tomatoes the size of marbles to huge ones the size of grapefruits. They also come in different colors, from the usual red to green, purple, yellow, orange, and even striped! Tomato plants need some care to grow, but even a new gardener can grow a crop.

• Tomato plants take a lot of care.

• There are many different types of tomatoes.

• Tomatoes are a good addition to a vegetable garden.

People once thought that the great Egyptian pyramids were built by slaves. But recent discoveries show the pyramids were probably built by skilled craftsmen. To build the pyramids, people had to apply skills in geometry and architecture, and move large blocks of stone. Building the pyramids took time and experienced tradespeople.

• To build pyramids, people had to know geometry and architecture.

• Recent discoveries are still being made about pyramids.

• The pyramids were probably built by skilled tradespeople, not slaves.

Have you ever noticed that there are many different markings on the road? These markings keep drivers safe on the road. White lines along the edge of the road show where the road ends. White or yellow dashed lines mark the different lanes. A double yellow line tells you that traffic will be going in the other direction on the other side.

• The markings on the road signal different things to drivers.

• Road signs keeps drivers safe.

• Double yellow lines indicate two-way streets.

Magnets have many uses, but one of their strangest uses is inside a cow’s stomach. They are put there so when cows accidentally eat nails or wire the metal sticks to the magnet. If the metal moved through the cow’s digestive system it could cause damage. The magnet protects the cow and saves the farmer from big vet bills!

• Farmers use magnets to prevent metal from puncturing cows’ stomachs.

• Metal can damage cows' stomachs.

• Magnets have many uses.

The United States sent seven manned missions to the moon, but only six made it. The Apollo 13 mission was over halfway to the moon when one of its oxygen tanks exploded. The astronauts had to come up with creative ways to fix their ship and return to Earth. Their courage has been an inspiration to others who followed in their footsteps.

• The Apollo 13 oxygen tank exploded.

• The United States has sent seven manned missions to the moon.

• The Apollo 13 mission was almost a disaster, but made it back safely.

It was difficult to build a subway in Rome, Italy. It wasn’t the rock that caused problems, though. Instead, construction crews kept finding Roman ruins. Every time they found a new ruin, they had to stop construction so experts could come and look at the site. Several times, they also had to change the route to avoid ancient sites.

• There are many buried treasures in Rome, Italy.

• Building a subway in Rome was hard because of the ruins under the city.

• Construction workers take great care with ruins.

Many forest fires are started by lightning strikes or other natural causes. However, most forest fires are started by humans being careless. People toss cigarettes or leave a few embers burning in a fire pit. All it takes is a few leaves to catch fire without someone noticing. This is why Smokey says: Only YOU can prevent forest fires!

• Most forest fires are started by natural causes.

• A few embers can cause a large fire.

• Most forest fires are caused by human carelessness.