definite article - What pronoun should i use if i want to indicate something in general

When I want to use “the” definite article to refer to things in general like:

• The cow is a useful animal; pronoun ...


• The doctor works in hospital; pronoun ...


• The lion is the king of the forest; pronoun...

So if I want to expound on the sentence further more and add a new sentence; which pronoun “anaphor” should I use.