Answer: Layers of the Epidermis. The epidermis is the outermost layer of our skin. It is the layer we see with our eyes. It contains no blood supply of its own—which is why you can shave your skin and not cause any bleeding despite losing many cells in the process.
The occupation of different niches on the open plains and woodlands of Africa by the zebras and the wildebeests is a result of niche partitioning. The zebras and the wildebeests in a common niche would compete for food, water, shelter, and space. This competition would affect the population growth of the two species by negatively affecting their reproductive capabilities. Thus, in the same habitat, the two species choose to occupy two different niches such that the competition between them is minimised. Hence they end up in separate niches.
Well, considering that seagulls, bears, and cows are warm blooded mammals, and spiders are arachnids with an exoskeleton, I'm willing to bet that spiders are ectothermic. And isn't the word exothermic?