Which is a requirement for natural selection to occur?
(a) heritable variations for some traits
(b) the ability of an organism to improve a trait during its lifetime
(c) equal probability of survival for all offspring
(d) fewer offspring than the environment can support

(c) equal probability of survival for all offspring

Natural Selection, Survival of the fittest favors the “fit” and adaptable to survive in the harsh and hostile environment. Organisms that has a Type 3 survivorship curves has high reproduction rate since it also has greatest mortality rate. And why does natural selection favor these type of organisms is because these organism first-handedly were able to “adapt”. The theories states that organism need to be adaptable to survive hence, their reproductive mechanisms were stimulated and improved with the awareness of the susceptibility and vulnerability of these type of species.   

I'm sorry to hear that. i will try to answer your other questions if it is within my ability. : )answers: my favourite colour is black.my favourite food is pasta.my favourite school subject is english, but i do also like lunch time.my least favourite subject is history as well as geography. i have currently garnered a quite equal hatred for both of the subjects.what about you? well, you for the points. : )