Pollen grains can be stored for several years in liquid nitrogen having a temperature of:

1.	–120 °C	2.	–80 °C
3.	–196 °C	4.	–160 °C

In the majority of angiosperms:

Which one of the following plants shows a very close relationship with a species of moth, where none of the two can complete its life cycle without the other?

The ovule of an angiosperm is technically equivalent to:

1. megasporangium

2. megasporophyll

3. megaspore mother cell

4. megaspore

Flowers which have single ovule in the ovary and are packed into inflorescence are usually pollinated by:

1. Bee

2. Wind

3. Bat

4. Water

A dioecious flowering plant prevents both:

1. Autogamy and geitonogamy

2. Geitonogamy and xenogamy

3. Cleistogamy and xenogamy

4. Autogamy and xenogamy