When animals habits are destroyed animals don't have any were to live and they run out of food. Then animals start to die because they don't have any were to live. Also they don't have enough food and then other animals will die because they used to eat those animals but those animals got extinct.
Living things are connected because animals might eat other animals like a lion might eat a deer and like Wildebeests eat grass and then the lion eats the Wildebeests and they might be connected because they are friends like the two ducks on the picture above.
PG:340, 341, 339, 338, 342, 343 those are all of the pages in my Lead 21 theme reader.