a. Exarch and endarch

b. Stele and vascular bundle

c. Protoxylem and metaxylem

d. Interfascicular cambium and intrafascicular cambium

e. Open and closed vascular bundles

f. Stem hair and root hair

Solution:

a.

1. Exarch is a condition where the protoxylem is present towards the periphery . The metaxylem is present towards the center.

2. Endarch is where the protoxylem is present towards the center.The metaxylem is present towards the periphery

b.

1. A stele is the central part of the root or stems.

2. A vascular bundle is a part of the stele which consists of phloem and xylem tissues.

c.

1. Protoxylem has narrower vessels and tracheid. Formed earlier than metaxylem.

2. Metaxylem has wider vessels and tracheid than protoxylem. Later formed xylem is called metaxylem

d.

1. Interfascicular cambium is present in between the primary xylem and primary phloem.
2. Intrafascicular cambium is present in between the two vascular bundles making the cambium continuous and forming a complete ring of cambium

e.

1. Open vascular bundles are capable of secondary growth and have cambium present between xylem and phloem.

2. The closed vascular bundles are not capable of secondary growth as they lack vascular cambium.

f.

1. Stem hair is multicellular and they are epidermal outgrowths known as trichomes and it is present all over the plant.

2. Root hair is unicellular are unicellular elongations of epidermal cells that are restricted to the root area of the plant.