What is required for natural selection to occur

Reproduction, heredity, and variation are important for natural selection to occur. Reproduction is the process by which one organism give rise to new organism so the traits that are more suitable for a species survival will be selected over non- suitable traits over many generations.

Heredity also plays an important role in natural selection simultaneously with reproduction because the advantageous trait that evolved during several reproduction is passed to the next generation by parents which confirms the survival of their offspring.

Variation occurs in a gene that can be transferred to the next generation. Variation that is helpful in a population to survive are favored by natural selection.  

slitherio is the original. its the best friend of all middle schoolers. the man you can count any time you have some free time. slitherio is the guy you hang with while you're in the computer lab suppose to be doing "research or whatever". slitherio isn't just a game but a friend.

wormaxio is just a fake trying to squeeze its way into the friend group. trying to pretend its cool and your best pal but how long has it really been there for you, really. it only wants you as friend to boost its social status. wormaxio is just annoying fake pleb. no offense

you and have a wonderful day

when a reversible reaction is occurring in both directions at the same rate; the products and reactants do not change in concentration. a chemical reaction where the compound is broken into its constituent parts.