Questions

Nostoc is a prokaryote. Prokaryotic cells lack membrane bound organelles and well organized nucleus, that is nuclear envelope is absent in these cells.

The nuclear envelope, also known as the nuclear membrane, a bilayer membranes which surrounds the nucleus, and in eukaryotic cells it encases the genetic material.

Papayas are yellow due to the presence of carotene and xanthophyll pigments i.e, Caricaxanthin present in the chromoplasts of the fruit pulp.

The coloration of the different tissues in plants is due to the plastids which are present in the cells. Leucoplasts are white in colour, chloroplasts are green in colour and chromoplasts are of various colours. These plastids can take any colour at different time. Therefore, green fruits ( chloroplasts) turn colurful (chromoplasts) at maturity.

'Are’ needs to be replaced with ‘is’ to make the sentence contextually correct. This is because, ‘in subject verb agreement, we match the subject with the nearest verb or the verb with the nearest or the first subject. But the verb should be matched with the main subject of the sentence’. Here the main subject is ‘Ignorant’ which is singular and so is followed by a singular verb.

‘Cured’ is followed by the preposition ‘of’. Thus, the correct sentence would be, ‘He will be cured of his fever’.

North sea is the largest fishing ground while the North-West pacific is the greatest region