SB 11.24.18

yad upādāya pūrvas tu
 bhāvo vikurute ’param
ādir anto yadā yasya
 tat satyam abhidhīyate
Synonyms: 
yat — which (form); upādāya — accepting as the ingredient cause; pūrvaḥ — the previous cause (such as the mahat-tattva); tu — and; bhāvaḥ — thing; vikurute — produces as transformation; aparam — the second thing (such as the element ahaṅkāra); ādiḥ — the beginning; antaḥ — the end; yadā — when; yasya — of which (product); tat — that (cause); satyam — real; abhidhīyate — is called.
Translation: 
A material object, itself composed of an essential ingredient, creates another material object through transformation. Thus one created object becomes the cause and basis of another created object. A particular thing may thus be called real in that it possesses the basic nature of another object that constitutes its origin and final state.
Purport: 

One may understand the purport of this verse through the simple analogy of a clay pot. A clay pot is formed from a lump of clay, which is itself prepared from the earth. In this case earth is the original ingredient forming the clay lump, and the clay lump is in a sense the original cause of the pot. When the pot is destroyed, it will again assume the designation clay and ultimately merge back into the earth, its original cause. In relation to the clay pot, clay is the beginning and final state; thus the pot is called real, for it possesses the essential characteristics of clay, which exists before and after the existence of the functioning instrument known as the pot. Similarly, earth exists before and after the clay, and thus clay may be considered real because it possesses the essential characteristics of earth, which exists before and after the existence of the clay. Similarly, earth and other elements are created from the mahat-tattva, which exists before and after the existence of the elements, which may be considered real because they possess the essential characteristics of the mahat-tattva. The mahat-tattva is ultimately the creation of the Supreme Personality of Godhead, the cause of all causes, who exists after all is annihilated. The Absolute Truth is the Supreme Lord Himself, who step by step gives meaning and character to all that exists.