Cells in some filamentous cyanobacteria that are specialized for nitrogen fixation are called:

1. Phycobilisomes

2. Chromatophores

3. Grana

4. Heterocysts

The cyanobacteria are also referred to as

(1) protists

(2) golden algae

(3) slime moulds

(4) blue-green algae

Oxygenic photosynthesis occurs in

(1) Chromatium

(2) Oscillatoria

(3) Rhodospirillum

(4) Chlorobium

Identify the labelled part in the given figure and select the correct option.

Heterocysts present in Nostoc is specialised for

(1) fragmentation

(2) nitrogen-fixation

(3) symbiotic relation

(4) food storage