if potassium-40 goes through 3 half lives how many years have gone by and what percentage of the original mass would remain ?

After another 1300 million years ( two half lives or 2600 million years) 100 /2 = 50 g decays and 50 g remains left . After another 1300 million years ( three half lives or 3900 million years) 50 /2 = 25 g decays and 25 g remains left.

Explanation:

well for one plants are always the producer, so a is the answer. a wolf is more of the consumer(predator) and the deer is the prey so i know those two are out of the question. also mushrooms are fungi/fungus so a is the producer.

im not intirely sure but i think the anwser is d relative humidity