Which planet do most known extrasolar LEAST resemble?

It is very rare that a planet resembles Mars, in fact it is the rarest type of planets among the known planets so far. Even the planets that do share some characteristics with Mars, they also have characteristics that make them different, especially their size and distance from their star.

r just means there's a number of carbon in teh chain. for example rcooh means that after x number of carbon, the chain ends with cooh.

explanation:

- lead + phosphoric acid = hydrogen + lead(ii) phosphate