Polish was my first language so I was glad to be able to recognize 'requin' as 'rekin' because that's 'shark' in Polish, I love making these small ties within different languages.
Same question. In English, using "the" in this sentence is really bizarre. This particular shark is an animal while the rest of them are not? "A shark is an animal" would be far more meaningful. Is it any different in French?
One doesn't elide between 'est' and 'un"? Don't pronouce the 't' of 'est'?
It's an optional liaison, generally pronounced in formal contexts (higher registers) but less so in contemporary informal contexts, so both are acceptable. This page has more info: http://french.about.com/library/pronunciation/bl-liaisons-o.htm
Hmm I'm not so good in english, But is it ok to say "the shark is a animal"?
It isn't proper. So no. Use an if the following word starts with a vowel sound, and a if it starts with a consonant sound.