John Allen, age 9, of Indianapolis, Ind. for his question:

How do flowers get their scent?

In the plant world, almost everything is a do it yourself project. Every green plant that grows makes its own food. The ingredients plants use are air, water and chemicals dissolved in the soil. Their basic food is a sugary substance. They can make this only during the day, because they need sunlight to process the ingredients and put the sugar recipe together. However, plants do not stop their food processing when the sun goes to bed.

During the night, they re make their sugar supplies into all the dozens of different things they need. They make woody cellulose to build their cell walls, also a variety of fats and oils, starches and carbohydrates. They make the green chlorophyll that colors their leaves, and lovely colors for their flowers. The tinted flower petals are made from boxy little cells. Here and there, tucked in among these cells, are tiny pockets. These are filled with special oily substances. When the petals open, these oils evaporate into sweet scented gases that spread through the air.