Hei, tas ir elona muskusa bruņurupucis

The authors use the word “backbone” in lines 3 and 39 to indicate that

Jim has found that he must consume 2,300 calories a day to reach his health goals, but he doesn't want to give up his afternoon snack of pretzels. unfortunately, he tends to eat the entire bag — which amounts to 1,300 calories! what strategy should jim use to improve his habits?

How are brightness and size related when it comes to stars