Question

what is granum ,thylakoids and stroma????

Answer 1

Thylakoids are flattened sacs in a chloroplast.
The pile of thylakoids are called grana and they lies in a colourless ground substance called stroma

Answer 2

lamelle are closed ,flattened, membrane bound ovoid sacs called thylakoids.
matrix is colourless ,granular ,colloidal ground substance called stroma.
thylakoids which lie colsely packed in piles called grana (singular granum). they contain green chlorophyll pigment molecule.