This text indicates that the basic component of scientific research is

A．It's of significance to make different reactions to the same things.
B．Scientific reasearch is unreliable owing to the different observations.
C．People try their best to make impartial observation.
D．The way of observation varies from person to person.

A．adapt to their environment.
B．control their environment.
C．adapt the environment to their need.
D．observe and understand their environment.