Bhagavad Gita Verse 5, Chapter 13

mahaabhootaanyahankaaro buddhiravyaktameva cha |
indriyaani dashaikam cha pancha chendriyagocharaahaa || 5 ||
 
The great elements, the ego, the intellect, the unmanifest, and also the ten senses, and the one, and five objects of senses.
 
mahaabhootaani : great elements
ahankaaraha : ego
buddhihi : intellect
avyaktam : unmanifest
eva : also
cha : and
indriyaani : senses
dasha : ten
ekam : one
cha : and
pancha : five
cha : and
indriyagocharaahaa : objects of senses
 
Nowadays, most computers have the ability to go into sleep mode, where all the running programs are saved in a file on the disk in such a way that they are brought back to life as soon as the computer is switched on again. Similarly, when the universe comes into existence, its entire state is restored from avyaktam, the unmanifest "file" containing the sum total of every unfulfilled desire. We then begin to see faint outlines of the universe, just like the computer first draws the outlines of the windows on the screen. This state is known as buddhi. We finally see the universe in full colour, in all its glory, just like we see a fully painted screen on our computer. This state is known as ahankara. This fully painted screen is created by combining three colours - red, blue and green - in various ways.
 
Similarly, the entire universe is created by combining the five great elements - space, air, fire, water and earth - in various ways. As humans, we are also comprised of those same five great elements. But, each of us looks and behaves differently than the other due to the difference in our "programming" - the avyakta, also known as vaasanaas or unfulfilled desires. Also, there is something within us that give us the ability to think, feel and act, which we do not see in inert objects. This is the inner instrument or the antahakarana. It is comprised of the buddhi or intellect which plans and decides, the ahankaara or ego which creates a sense of agency or I-ness and the mind which thinks and feels, referred in the shloka as "ekam" or the one.
 
The mind receives stimuli from five sense organs - ears, skin, eyes, tongue and nose which run after their objects - sound, touch, form, taste and smell, respectively. The mind also controls five organs of action - mouth, hands, legs, genitals and bowels. The five elements, the five sense organs, their five corresponding sense objects, the five organs of actions, the mind, the intellect, the ego and the unmanifest - these make up the twenty four categories of the universe mentioned in the Saamkhya school of philosophy.
 
In just one shloka, Shri Krishna has explained the entire process of cosmic creation and its building blocks, as well as the specific factors that enable humans to think, feel and act. Plants and animals are also made up of similar building blocks, although not as fully expressed as in humans. Whenever we develop anxiety or frustration that this world is becoming too complex to understand, we can refer to this shloka and understand that at its core, the world is quite simple. Also, whenever we develop the mistaken notion that we are independent and do not need anything from this world, this shloka shows us our oneness with the world. Now this shloka only provides a static view of the world. How do we account for all the dynamism, the movement, the give and take between one human being and the rest of the world? This is explained in the next shloka.