Because people are willing to pay for them.
There are so many you need a car make and model to tell you what engines are for that? all car engines are of the internal combustion type, fueled by gasoline.
Jaguars need a big space so they can hunt
NO. There are all KINDS of V-8 small block engines. 265,307,305,267,327,400,350 and so on. There are all kinds of Big block V-8 engines too. Just because it is a V-8 don't mean that its a big block are small block.
they need to breath
Steam trucks looked like steam trains, with large engines. They had big iron wheels and smoky funnels. They were so big and heavy that they ruined the roads.
No, they are way too big and they aren't the right colours to be camouflaged. They have no need to do so. They are herbivores so they don't need to hide from prey, and they are so big that they are in no danger from predators.
Most speed boats, especially with outboards, use gasoline engines. Larger vessels such as ships and commercial boats, generally use diesel. For raw power and performance, gasoline engines are still best. Big chevvy V8s are popular choice for powerboats with internal engines. Water and electrics (for the spark) do not mix well, so gas engines need to be maintained and looked after well and can be temperamental. For economy and reliability diesels are best. Which is why commercial vessels use them.
So we don't get killed
Thermodynamics is a branch of physics that was started after there was a need to understand the energy in superheated steam, so that steam engines could be made as efficient as possible. So thermodynamic is definitely part of mechanical engineering because it is now used in the design of all kinds of engines, piston engines, turbines etc.
small but we are a small town so we don't need a big school
the effect is that if the rock is to big the it wont go far so you will need a small rock. but if you want a big rock then you will need a big sling shot and it has to be strong.
Without search engines, such as google, WIKIANSWERS, yahoo, ask jeeves and so on, things would be rather hard to find on the internet. Think about it. The only thing you can do is type a random website address and hope it comes up in existans. For example: I need info on what to feed a dog, so with no search engine I do this. www.whatdoyoufeedadog.com (what-do-you-feed-a-dog) So there you have it. Search engines ARE important.