its deadly to people over 50
have learned
They have learned that Earth revolves around the Sun.
list three things that the scientists learned about earth in the 1800's?
What have scientists learned after close study of the chemical structure of the cell and its nucleus?"
The ax left no doubt that the Iceman lived after people had learned how to use copper.
The subject of this sentence is 'Scientists'.
As scientists have learned more about chemicals, they have become more aware of their dangers.
Which one? mars
that it is made out of red rocks
all artifacts
This question is silly but the answer is not obvious. Scientists have discovered that if you eat some one who has cancer you may get cancer yourself.
D. Telomerase