Q: Answer this question:

who has won the most men's tennis grand slam titles??

A: Roger Federer

Q: Answer this question:

we are concerned about ozone depletion in what layer of the atmosphere??

A: stratosphere

Q: Answer this question:

when was the first in vitro baby born??

A: 25 July 1978

Q: Answer this question:

when did the first earth day take place??

A:
1970