I need help on these 2 questions.

Which are causes of mechanical weathering? check all that apply.oacid raino plant growtho animal actionso carbon dioxideo pressure release

Working with si (metric) units for each of the following commonly used measurements, indicate its symbol. liter gram milliliter kilogram meter centigram milligram centimeter kilometer second millimeter milliseconds

How will the volume of a gas be affected if the pressure is tripled, but the temperature remains the same?