They are saying that every theory can eventually be changed a bit due to further research. It does not mean the theory is bad, just that it can become better.
I think its a Photosynthesis
The bottleneck effect is when the population of a species is reduced due to an environmental disaster or human activities. An example of the bottleneck effect is "Insecticide spraying eliminates all but a few of the beetles on an island". For the species to survive, the green beetle will either have to move to a new location and build a new colony or they will have to develop a resistance to the insecticide and then start to rebuild the existing colony
The right answer is A, Feldspar.
