Krishna refers to the physical body (𝙨𝙖𝙧𝙞𝙧𝙖𝙢) as 𝙆𝙨𝙝𝙚𝙩𝙧𝙖 (field) and explains briefly its characteristics, its cause and effect (𝙫𝙞𝙠𝙖𝙧) ; about 𝙆𝙨𝙝𝙚𝙩𝙧𝙖𝙟𝙣𝙖 (knower of the field) and the nature of His powers. He cautions that these were described by various sages and several spiritual texts in many ways (13.4 and 13.5). An important point is that 𝙆𝙨𝙝𝙚𝙩𝙧𝙖 and 𝙆𝙨𝙝𝙚𝙩𝙧𝙖𝙟𝙣𝙖 are described by various sages and texts in different ways. This is a universal problem where truth is described by different people in different ways in different languages making our understanding difficult. Krishna cautions about not getting lost in words.
Krishna says, "The fundamental elements, 𝙖𝙝𝙖𝙣𝙠𝙖𝙖𝙧 , intellect (𝙗𝙪𝙙𝙙𝙝𝙞) , unmanifested (𝙖𝙫𝙮𝙖𝙠𝙩𝙖) , ten senses, mind and the five objects of the senses (13.6). Desire, hatred, pleasure, pain, assemblage (material body), consciousness (𝙘𝙝𝙚𝙩𝙖𝙣𝙖) and persistence. This is 𝙆𝙨𝙝𝙚𝙩𝙧𝙖 briefly described with its modifications" (13.7).
The fundamental elements are fire (energy); three states of matter- earth (solid), water (liquid) and air (gaseous); and space to hold all of them. The five sense objects are sight for eyes, sound for ears, smell for nose, taste for tongue and touch for skin. The ten senses are five organs of perception (𝙜𝙮𝙣𝙖-𝙞𝙣𝙙𝙧𝙞𝙮𝙖) -eyes, ears, nose, tongue and skin and five organs of action (𝙠𝙖𝙧𝙢𝙖-𝙞𝙣𝙙𝙧𝙞𝙮𝙖) hands, legs, speech, generative organ and organ of defecation. The rest are various feelings generated in us which become a part of 𝙆𝙨𝙝𝙚𝙩𝙧𝙖 . The interplay between them is what we perceive as life.
Two surprise elements are unmanifested and consciousness (𝙘𝙝𝙚𝙩𝙖𝙣𝙖) which are usually considered beyond the human body. Krishna says that they too are a part of 𝙆𝙨𝙝𝙚𝙩𝙧𝙖 but not 𝙆𝙨𝙝𝙚𝙩𝙧𝙖𝙟𝙣𝙖 . An unmanifested tree is hidden in the seed and in that sense unmanifested is also a part of 𝙆𝙨𝙝𝙚𝙩𝙧𝙖 . Consciousness is still conscious of something or needs something for its existence. Hence, it is a part of 𝙆𝙨𝙝𝙚𝙩𝙧𝙖.