Best form of iterating over a lsit of lists

[Sagar]

@Larz60+ , I think @tonymcgregor is confused about the syntax of the for loops.
He wants to know the differences between following three codes (I also want to know):

for name, species, weight in pets:

for [name, species, weight] in pets:

for (name, species, weight) in pets:

Please let us know the differences.
:)