What would be the best technique to separate an insoluble solid from an liquid, like sand from water

they emit helium gas that attaches to nearby planets.

they remove low-mass elements from the planets’ crust.

they cause nuclear fusion inside the inner core of planets.

they produce heavy elements such as iron and gold.

explanation:

acid rain does not usually kill trees directly. instead, it is more likely to weaken the trees by damaging their leaves, limiting the nutrients available to them, or poisoning them with toxic substances slowly released from the soil. the main atmospheric pollutants that affect trees are nitrates and sulphates.