The respondent shall have 30 days in which to answer the petition. In case of service by publication, the 30 days shall not begin to run until the expiration of the period allowed for publication. In the case of a counterpetition for dissolution or legal separation to a petition for dissolution or legal separation, no answer shall be required to the counterpetition and the original petitioner shall be deemed to have denied each and every statement, allegation and claim in the counterpetition.