Question

Definition of exarch xylem.

Answer 1

It is a type of xylem in which first made xylem lies towards the outside later formed xylem.

Answer 2

Explanation:

Given: d=3

We know:

an=a+(n−1)d

∴a20−a15=[a+19d]−[a+14d]

                     =5d

                     =5×3

                     =15

Hence, the answer is 15.

Given: d=3

We know:

an=a+(n−1)d

∴a20−a15=[a+19d]−[a+14d]

                     =5d

                     =5×3

                     =15

Hence, the answer is 15.