its deadly to people over 50
The simple predicate is "have learned" because it shows the action or the verb that the subject "scientists" is doing.
They have learned that Earth revolves around the Sun.
list three things that the scientists learned about earth in the 1800's?
Which one? mars
that it is made out of red rocks
The subject of this sentence is 'Scientists'.
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
They learned alot about africa's life and culture.
they have learnt a bunch of new things
Most elephant shrew species were first described in the 1800s by scientists who classified them as shrewsbecause of obvious physical similaritie .