Like so: "The platypus's natural environment is a pleasant one".
The possessive form of "he" is "his": He did his homework after dinner.
No, it is singular, the possessive form of it is its. The plural form of it is they or them, and the possessive form is their.To answer the question directly: there is no such word as ITS'.
The possessive form is lawyer's.
The possessive form is whistle's.
The possessive form is posse's.
That would be the plural using Greek rules: both platypus and octopus are from Greek, and do not (as is commonly assumed) use the Latin plurals platypi and octopi.The correct English plural is either platypuses or the same word platypus (used as a group noun, like sheep or trout).
The plural possessive form is Luis's.
The singular possessive form of the noun "it" is "its". Note that there is no apostrophe in the possessive form of "it". The apostrophe is only used after "it" when used as a contraction of "it is".
The singular possessive form is heart's; the plural possessive form is hearts'.
The singular possessive is Richard's; the plural possessive is Richards'.
The possessive form for the noun science is science's.
The possessive form for the noun freedom is freedom's.