A common structural feature of vessel elements and sieve tube elements is:

1. thick secondary walls

2. pores on lateral walls

3. presence of P-protein

4. enucleate condition

Passage cells are thin-walled cells found in:

Palisade parenchyma is absent in leaves of:

1. Sorghum

2. mustard

3. soybean

4. gram

Guard cells help in:
1. protection against grazing
2. transpiration
3. guttation
4. fighting against infection

Anatomically, fairly old dicotyledonous root is distinguished from the dicotyledonous stem by:

1. absence of secondary xylem

2. absence of secondary phloem

3. presence of cortex

4. position of protoxylem

In barley stem, vascular bundles are:

1. open and scattered

2. closed and scattered

3. open and in a ring

4. closed and radial

The annular and spirally thickened conducting elements generally develop in the protoxylem when the root or stem is:

1. maturing

2. elongating

3. widening

4. differentiating

The chief water conducting elements of xylem in gymnosperms are:

1. vessels

2. fibres

3. transfusion tissue

4. tracheids