Any defendant has the right to appear in the proceeding and file an answer, in writing, with the clerk of the court, at any time prior to the date fixed for the hearing of the petition but not thereafter, in which answer said defendant shall set forth such legal objections as he may have to the condemnation or appropriation of any property owned by him or to the prosecution of said proceeding. At the time set for the hearing of said petition or such time to which the hearing may have been continued by the court, the court shall proceed to hear any objections raised by the answer, if any there be. The court has no power to inquire into the necessity of exercising the power of eminent domain for the purpose proposed, nor into the necessity of making the proposed improvement, nor into the necessity of taking the particular property described in the petition. If the court finds that the petitioner has the right to prosecute said proceeding and such objections as may have been filed are overruled, the court shall appoint three disinterested commissioners in condemnation, freeholders of real estate in said city or city and county and residents thereof, who shall have the powers and duties provided in this part 1. No person shall be disqualified to act as a commissioner by reason of the fact that he may own either the fee or other interest in or to property that might be assessed a special benefit on account of the proposed improvement.