We know how many seeds are in an apple……

……but only God knows how many apples are in a seed

Prabhupada, Mayapur, March 9, 1976:

tvam va idam sadasad isa bhavams tato ’nyo maya yad atma-para-buddhir iyam hy apartha yad yasya janma nidhanam sthitir iksanam ca tad vaitad eva vasukalavad asti-tarvoh

Cause and effect, sad-asad. One disappears, the cause appears, disappears, and the effect comes into being. The very good example is given here, asti-tarvoh. Asti means seed.

From the asti, from the seed, a big banyan tree comes out. At that time the asti, the seed, disappears. A tree is manifestation, so this is example of sad-asat. Asti, the seed, disappears, and the tree is manifest. So the creation of God is like that.

Therefore, in the Bhagavad-gita it is said, bijo ’ham sarva-bhutanam. Bija, asti, or seed, He is the root cause of everything. One seed, a small seed, grain, and hundreds of thousands trees coming out of it, and in each tree there are millions of fruits, and each fruit, there are hundreds and thousands of seeds.

Again, from the seed, the same creation, hundreds and thousands, millions and millions. This is God’s intelligence, how from one source so many varieties are coming out. Again, when annihilation takes place, they again go into the original seed, Krsna. Yanti mamikam, it is said. It’s coming out.

yasyaika-nisvasita-kalam athavalambya jivanti loma-vilaja jagad-anda-nathah visnur mahan sa iha yasya kala-viseso govindam adi-purusam tam aham bhajami [Bs. 5.48]

This material creation is done by Maha-Visnu. Maha-Visnu. The original Visnu, Krsna, He has nothing to do. Na tasya karyam karanam ca vidyate. Original God—isvarah paramah krsnah [Bs. 5.1] —
He is simply playing on flute and enjoying the company of Srimati Radharani.

He has nothing to do. And how things are taking place? Creation, He’s the creator? By expansion, svamsa. From Krsna the expansion is Balarama; from Balarama the expansion is Sankarsana, then Aniruddha, Pradyumna, like that, then Narayana, then again Sankarsana, Pradyumna, Aniruddha, dvitiya-catur-vyuha.

From this Sankarsana, Maha-Visnu. Therefore Maha-Visnu is described, kala-visesah. Yasyaika-nisvasita-kalam athavalambya jivanti loma-vilaja jagad-anda-nathah, sa iha yasya kala-viseso [Bs. 5.48]

This Maha-Visnu, from whom, by His breathing only, millions and trillions of universes are coming, and each universe there is a Brahma, jagad-anda-nathah. Just like in this universe there is one Brahma. He creates again so many demigods, animals, human beings in each universe.
Full Lecture