Natural selection acts on populations through a specific trait. Which statement must be true about that trait? 1. The trait is the same for all organisms. 2. The trait has little impact on survival.
3. The trait is resistant to mutations.
4. The trait is passed on genetically to the next generation.

Which is not a likely outcome after extensive irrigation of dry farmland? useless, unproductive soil salinization of the soil depletion of groundwater nutrient-rich soil

Which event would lead to primary succession of a forest?

Which statement best describes how the loudness of the sound affects the high-pressure region created by the sound wave? a. a louder sound has no effect on the pressure created. b. a louder sound means a high-pressure region that is higher. c. a louder sound means a high-pressure region that is not as high.