Natural selection lead to different species when the squirrels were separated, some of them acquired traits better suited for their new environment. This allowed them to survive and reproduce better than others. Over time, each group evolved to display unique traits for their different environments until one species evolved into two.
Explanation:
The speciation in the squirrels due to the barrier in canyon occurred due to this. Such speciation is called allopatric speciation.
Speciation leads to formation of new species from the existing species due to change in their habitat or physical structure.
The squirrels on the two different side of canyon adapted to the habitat they are in. Their reproductive cycles, habitat and adaptation mode has become different due to the change in environment.
The species of squirrels became two as they reproduce and passed on the traits for survival in the environment which they had adapted.
The squirrels have become <em>reproductively isolated</em> also.
Genetic divergence takes place due to natural selection as squirrels arenow two different species.
Organs.
if you're having trouble remembering them they are
cell
tissue
organ
organ systems
organism
Acid rain can be very harmful, mildly harmful, or not harmful at all. It mainly depends on the density of the rain, and how bad the current air pollution in the area is. Also, it depends on how often the area gets acid rain. The first few times an area gets acid rain, it's nearly harmless. Then, the next few it can be very dangerous, but eventually gets weaker over time. More air polluted areas are more likely to get much more harmful acid rain.
Summary: Acid rain is usually mildly harmful, mostly only harmful to infrastructures.<span />
Answer:
3rd
Explanation:
Cellular respiration occurs only in animals
