Any person interested may oppose any such petition, and file his demurrer or answer thereto on or before the third day of the term of court named in said publication notice, unless the time be extended by order of court, and may also file a cross petition if he or she desires to do so. Said answer shall admit, confess and avoid, or deny all the material allegations of the petition, and shall, except when made by guardian ad litem, be verified by the affidavit either of the respondent or his agent, in the same manner as above required in cases of the petition. Said answer shall have no other or greater weight as evidence than the petition.