There are three main differences between nuclear and mitochondria DNA (mtDNA): 1.) mtDNA is circular, whereas nuclear DNA is linear. (Both are double stranded) 2.) mtDNA is (generally) uni-parentally inherited, in most animals (not mussels though for example), mtDNA is passed from mother to offspring. from wiki
The mass of the object and its speed.
The excerpt that tells the White family's uncertainty on the Major's story would be when Mr. White said:
"If the tale about the monkey's paw is not more truthful than those he has been telling us," said Herbert, as the door closed behind their guest, just in time to catch the last train, "we shan't make much out of it." This is because they are not sure what is true about the information that a stranger told them in the train.
I believe this is a metaphor, as it refers to one thing in order to show or suggest they are similar. The phrase means that, as how a desert can survive winds and remain steady, so is their love for each-other. No matter what happens, Fatima and Santiago’s love will forever be true-hearted and faithful. Hope this helps!