What prevents multiple sperm from fertilizing an egg? A. The egg reacts to a sperm penetration by blocking other sperm.
B. Nothing prevents it, this happens frequently,
C. Only one sperm on average ever reaches the egg.
D. A toxin released by the sperm and the egg cell

It feels feed the echo system

The soviet union beat the us to the first successful launch, with the october 4, 1957, orbiting of sputnik 1, and later beat the us to have the first human in earth orbit, yuri gagarin, on april 12, 1961. the "race" peaked with the july 20, 1969, us landing of the first humans on the moon with apollo 11