List 2 underlying causes of water pollution

The climate of the continental united states is generally 1. tropical 2. temperate 3. arctic 4. highland

Find the mass in grams of 1.37x1020 particles of h3po4

How can a give a full method for the experiment of separating sand from water by filtration? 1-materials 2-steps 3-conclusion also for water and salt separated by the evaporation or distillation process