Answer A:
1. Spiral chloroplast:
This organelle help in photosynthesis, because it contain green pigment called chlorophyll in which water and carbon dioxide combine in the presences of sun light to prepare glucose.
2. Cell wall:
It is chemically composed of<span> an outer layer of pectin and an inner layer of cellulose. It provide rigidity and shape to spirogyra cell.</span>
Answer B:
The other parts which are not labelled include mucilage, cytoplasm, pyrenoids, cytoplasmic strand.
Answer C:
Function of pyrenoid:
<span>Each chloroplast strand has several round bodies called 'pyrenoids', which are responsible for starch production.
</span>Function of mucilage:
Mucilage help in retaining water in cell.
Answer:
Wind.
Explanation:
Gymnosperms are also known as naked plants as their ovules are in the unfertilized state and their seeds do not bear fruits. Gymnosperms are known as seed plants.
Gymnosperms pollen grains are transferred from the pollen cone to the ovule. Their pollen are generally transferred by winds as they are lighter and resistant to water. Sometimes, insects are also responsible for the transfer of pollen grains.
Thus, the correct answer is option (b).
No, it should be 2Na + 2H2O------> 2NaOH +H2