Final answer:
The subject is Biology and the organism being described has small but complex eukaryotic cells, is commonly used in molecular biology studies, and has larval cells with giant chromosomes for gene expression studies.
Step-by-step explanation:
The subject of this question is Biology as it relates to the characteristics of a particular organism.
The organism being described has the following characteristics:
- Small but complex eukaryote: This means that it is a small organism with complex cellular structures.
- The favored animal for the molecular biology of development and the neurological basis of simple behavior: This means that this organism is commonly used in studies related to the development of organisms and the biological basis of simple behaviors.
- Certain larval cells have giant chromosomes, whose individual genes can be identified for studies of gene expression: This means that the larval cells of this organism have large chromosomes, allowing for the study of gene expression on an individual gene level.