When does a mutation have the most impact on allele frequency

Which of the following is a consequence of urban heat islands? increased precipitation downwind of the city? increased precipitation upwind of the city? decreased winds within the city? increased winds within the city?

Transmission electron microscope are best for viewing a) microorganisms in pond water b) internal organs of a mouse c)internal structures of a cell d) surface features of a specimen

The fruit of a certain plant is sweet and fleshy. the seeds of this plant have a seed coat that is fairly tough. the seeds germinate better if they are exposed to acid, or scarification. what is the most likely type of dispersal for this seed? water animal wind