No they don't
For example humans. Technically humans are place below a wild predators such as sharks in trophic levels.
But the fact is we can eat sharks. So , organisms don't always stay in the same level
Not really sure on that one but I can answer the question below called Define Osmosis. :)
C. The Composition of your blood
Answer:
Yes earth is only so big
Explanation:
SUPOSSEBLY IN 2035 we will have a small civilization on mars. Cause in 1 million years or less humans will be over populated on earth and forced to make room underground or higher in the skies like outer space!