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the trees in the forest. The trees are full of life and sound. Birds squawk and chirp. Monkeys call out to one another. Snakes hiss and slither along branches. This morning, the forest is fi lled with a


S


new sound. It begins as a faint buzzing. The buzzing grows louder and louder. Suddenly, a man flies over the treetops.


The buzzing is coming from a winged machine strapped to his back. Meet Mark Olson. He’s a botanist. He studies trees. The machine he’s using is a paraglider. He zips over the treetops to look at leaves. He wants to fi nd out how leaves gather and use sunlight. He knows it is one of the keys to a tree’s survival.


Leaves at Work Olson gets ready to land. He flips a switch, turning off the motor. T e glider gently carries him to the ground. He lands near the trees he’s been studying. T ey’re called moringa trees. Moringa trees fascinate him. People use


their leaves and roots for food and their bark for medicine. Some people call them miracle trees. To


Olson, the miracle is what happens inside each leaf every day. Like all green plants, trees make their


own food. Leaves use the sun’s energy to mix water with carbon dioxide, a gas in the air. T is makes food for the plant. It also gives off oxygen. We call this process photosynthesis. T is process is as important to us as it is


to the tree. We breathe in the oxygen that the tree gives off . T is creates a cycle of life. It keeps life on Earth going.


20 oxygen is released


unlight flickers through the leaves of


Using Sunlight Olson looks up at the leaves of one large tree. He squints a little. It is bright and sunny now. Yet each night, this tree waits through the darkness for the first rays of the sun to appear. As the sun comes up, it begins to warm


the tree’s many leaves. Tiny pores on the leaves open. A little bit of water evaporates through them. Carbon dioxide from the air goes into the pores. Inside each leaf, chlorophyll soaks up the sunlight. At the same time, the moringa’s roots


take in water and minerals. T e roots reach deep into the soil. Water travels up the roots to the trunk. T en the water flows into the tree’s branches and into each leaf. Each leaf makes only a tiny amount


of food. So the more sunlight the leaves capture, the better. A grown moringa needs thousands of leaves to keep it alive. Together, the leaves have until evening to make food to feed the tree.


A leaf turns sun, water, and carbon dioxide into food and oxygen.


light energy enters leaf


water enters leaf


sugar leaves leaf


PHOTOSYNTHESIS


carbon dioxide enters leaf


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