What was used as an ancient poison but it's a necessary nutrient in our body

Felipe is saving money for a class trip. he already has saved $ 2 5 0 $250 that he will put toward the trip. to save more money for the trip, felipe gets a job where each month he can add $ 3 5 0 $350 to his savings for the trip. let m m be the number of months that felipe has worked at his new job. if felipe needs to save $ 2 7 0 0 $2700 to go on the trip, which equation best models the situation?

What percentage of the earth's water is available for use by living things?

Did the universe cool off or get hotter as it expanded after the 'big bang"?