Which of the following is a valid scientific hypothesis?

a. suvs are ruining the climate

b. desert mesas are beautiful

c. offshore drilling should be illegal

d. earth-like planets exist elsewhere in the universe

D, or 'earth-like planets exist elsewhere in the universe' is most correct. Though based on technicalities, none of them are. A proper hypothesis follows the formula of 'if-then-because.' For example, I could say that 'if prices of chocolate are lowered for a sale, then sales will go up by __% because statistics say __% of people are more willing to buy something perceived to be off lower cost than before.' Of course, that was a lousy example, but I hope you get the idea.