Some rivers begin in mountains or hills, where rain water or snowmelt collects and forms small channels, . At first, the channels are small and are called rills. As more water enters the channels they grow forming gullies (larger channels). The streams in the gullies eventually become big enough to form a river
Answer b (probably wrong)
Acidic solutions have pH of less than 7. Neutral have pH of 7. Basic solutions have pH higher than 7.
