Among the following sets of salient features, which set does not exclusively characterize mammals? (1) Presence of sweat, glands, hairs on skin and diphyoclonts (2) Presence of mammary glands, sweat glands and diaphragm (3) Presence of mammary' glands, sweat glands, and diaphragm (4) Presence of mammary glands, hairs on skin and diaphragm.