The two texts being compared are texts about tigers. Text A is an extract from The Life of Mammals by David Attenborough, Text B is from Life of Pi by Yann Martel. The texts discuss tigers and their characteristics, but from very different points of view; Text A is from a non-fictional book of mammals, Text B is a passage from a novel.
Text A describes tigers from a distance. The extract involves statistical details about the body size, shape and fur colour. There is no personal touch to the text, and even if the author has seen tigers, it doesn't show. He maintains a professional distance and discusses issues objectively. He does, however, try to make the official-seeming text more interesting: "They have short snouts and high-domed skulls, which provide attachments for massive jaw muscles. And they have the sharpest teeth and the longest canines. They are the cats."
The author tells many details before he mentions what he is talking about, which builds up the reader's interest. It also implies that this is not a book meant for studying mammals in school; it would be very confusing for anyone trying to learn this for school to try to memorise facts without knowing what you are reading about. The use of superlative emphasises that "they" really are the strongest and most dangerous.
On the contrary to text A, text B leaves the statistical details to a minimum and tells about how the main character feels about tigers. The man radiates a deep respect and fear towards the animal: "The stance had something of a pose to it, as if it were an intentional, even affected, display of mighty art. And what art, what might. His presence was overwhelming yet equally evident was the lithesome grace of it."...