A four-year-old tree with a woody trunk experienced optimal growing conditions during its first two years of growth and drought conditions during the most recent two years. Describe the relative width of the tree's four growth rings.

First two rings are thicker while the last two rings are thinner.

Explanation:

Due to the first two years of optimal growing conditions received by the tree, the width of trunk of the tree is thicker but due to drought conditions experienced by the tree during the most recent two years, there is very little increase occur in the width of the trunk because the tree is in stress condition   and for that reason the ring of trunk is thinner as compared to first two years.

a=c and then d= c because of the band so you get ac/dc and you add them together you get sound waves