(a) (i) The thread-like non-reproductive structures in Rhizopus are known as hyphae. (ii) Sporangia develop at the tips of the non-reproductive threads in Rhizopus.
(b) In the fungus, Rhizopus, some specialised hyphae give rise to a globular structure (known as sporangium) that contains spores. The sporangium bursts to release spores. Each of these spores germinates to produce a new individual. Since the spores disperse through air, they can land on various sites. These sites may be favourable or unfavourable. During unfavourable conditions, these spores are protected by their thick walls until they come in contact with some favourable conditions.