When studying the world of living things, biologists and other scientists use the scientific process. Observtions along with precious data are used to formulate a hypothesis. New observations and or experiments are carried out in order to test the hypothesis. Scientists often do controlled experiments. The control sample does not go through the step being tested and this acts as a safeguard against a wrong conclusion.

what is the topic and stated main idea..
I think the topic is observations
and the stated main idea is when studying living things, biologists and other scientists use the scientific process.
not sure tho.. thanks in advance

I agree with your main idea. But I think the topic is studying living things.

The topic of the passage is the scientific process in the study of living things. The stated main idea is that when studying living things, biologists and other scientists use the scientific process, which includes making observations, formulating hypotheses, conducting experiments, and using control samples to obtain accurate results and prevent incorrect conclusions.