A party shall state in short and plain terms his defenses to each claim asserted and shall admit or deny the averments upon which the adverse party relies. If he is without knowledge or information sufficient to form a belief as to the truth of an averment, he shall so state and this has the effect of a denial. Denials shall fairly meet the substance of the averments denied. When a pleader intends in good faith to deny only a part or a qualification of an averment, he shall specify so much of it as is true and material and shall deny only the remainder. Unless the pleader intends in good faith to controvert all the averments of the preceding pleading, he may make his denials as specific denials of designated averments or paragraphs, or he may generally deny all the averments except such designated averments or paragraphs as he expressly admits; but, when he does so intend to controvert all its averments he may do so by general denial.