Final answer:
A giant chromosome consisting of many identical copies of a chromosome lying next to each other in parallel is known as a Polytene chromosome.
Step-by-step explanation:
A giant chromosome consisting of many identical copies of a chromosome lying next to each other in parallel is known as a polytene chromosome. Polytene chromosomes are formed when multiple rounds of DNA replication occur without cell division, resulting in the formation of hundreds of chromatids that are attached together in parallel.