Science 1. Suppose you were stranded on a desert island without a calendar or clock. How would you know when a day, a month, or a year had passed?
2. How could you tell what time of year it was?

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.

"record the time to complete a chemical reaction" would most likely be part of a lab procedure.