A timber merchant told to the customer that log of wood he is purchasing belongs to $20$ years old tree. He did so by
Measuring wood log
Counting annual rings
Counting cork layers
Measuring breadth of wood
Histogen theory states that epidermis is derived from the
Abaxial surface of the leaf generally bears
Cystoliths sometimes deposited in plant cells are crystals of (aggregation of)
Axillary bud originates from