Black fur(b) in guinea pigs is dominant over white fur(b). find the probability of a hybrid offspring in the cross: bb x bb. 0% 25% 50% 75% 100%

If you were referring to a cross between BB and Bb genotype then the answer would be 50%.

You can figure this out by making a Punnett Square.
       B      b
B   BB    Bb
B   BB    Bb

If you look at the result there is a chance that 2 out of the 4 will have a mixed genotype of Bb. The probability would then be 50%. 

No because the eaeht is on a 23.5 degree axis tilt and so when it is winter the northern hemisphere is pointing away from the sun and the soutubern hemisphere is pointing toward the sun