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 />
In what organisms are you referring to?
The True statements are.
Organisms in a population must compete for the resources as the resources are limited and the organism that compete and survives wins.
The best equipped organism survive which is known as the survival of the fittest.
Over the time due to challenges in the environment the beneficial variation takes place in the organisms and it spreads through the generations and then it gradually changes the whole population.
The false statement is Organism of the same species are equipped with the same survival skills.
The organism of the same species have some variation and because of this variation they compete and win against the other member of the same species.