Draw a nonsubstituted alkane that can exist as one of only two isomers.

An example of nonsubstituted alkane that can exist as one of only two isomers is Butane with molecular formula . 

Isomers are those having the same molecular formula but different chemical structure.

Non-substituted alkane means it is not substituted by any other atom.It has only carbon and hydrogen atoms attached to it.

It was said to have happened by earthquakes, the shifts in the tectonic plates moved everything 

The rate that would change would be the  searching efficiency/attack rate. there are only two other rates in this model: the  growth rate of prey, and the  predator or consumer mortality rate.the  searching efficiency/attack rate is what indicates how effectively can a predator capture its prey whether in the searching process or actual capturing/attacking process.