You and all organisms live in an environment. An environment is made up of everything that surrounds an organism. It can include the air, the water, the soil, and even other organisms.
An organism responds to changes in its environment. When an organism responds to a change, it reacts in certain ways. All living things respond in someway.
Have you ever noticed how plants and insects respond to light? Plants bend toward light. Insects fly toward light.
Living things also respond in other ways. The leaves on some trees respond to a change in season. In autumn, they change colors and then fall off the branches. Animals also respond to a change in season. Squirrels save nuts for the winter. Bears sleep through the winter in a cave.
You respond to your environment in many ways, too. You may shiver if you are cold. What other ways do you respond to changes in your environment? (156 words)
Useful Words and Expressions:
react vi. 反应，起作用
react against oppression反抗压迫
react on each other相互起作用
Unkindness often reacts on the unkind person.恶人有恶报。
The eye reacts to light.眼睛对光有反应。
The audience reacted readily to his speech.观众对他的讲演立即起了反应。
a hard [tough] nut to crack棘手之事；难对付的人
a tough nut果断顽强的人；难对付的人，无赖汉
He who would eat the nut must fiDt crack the shell．不打碎果壳，就吃不到果仁；不劳则无获。