Упр.2b Уроки 3-4 Юнит 6 New Millennium English 11 класс

1. 2 B. Read the introductory chapter from the textbook Biology for Life and see if you can finish Ex. 2A.
   • What is that structure for?
   • How does it work?
   • Why is the animal behaving like this?
   • Why are weeds growing here but not there?

Scientists observe things and ask questions about them. They put forward a possible reason, called a hypothesis, and then test it by carrying out an experiment. This procedure is called the scientific method.

To test the hypothesis that light is needed for the leaves of a young plant to become green, scientists put one plant in the dark and another one in the light. The plant in the light is the control, because it provides a standard for comparison. In a controlled experiment, all the variables are kept constant except for the one being investigated.