Using the chart, determine the amount of Co-57 present on January 21 if you had a sample of 8g on January 1st. A) 2 g B) 4 g C) 16 g D) 25 g

A)2 g

Explanation:

According to the graph, the half-life of Co-57 is 10 days. In twenty days (the amount of time between Jan 1 and Jan 21), two half-lives have passed, and, therefore, the amount of the sample has decreased by 50% twice. After the first ten days, 4g remain; after the second ten days, only 2g are left.

i think the answer is a, hope this is right, that would be my best guess.

co2reflects heat radiation back to earth buning coal and oil emits co2 globe warms