Final answer:
Streptococci are round-shaped bacteria that form chain-like structures.
The correct option is d.
Step-by-step explanation:
The shape and form of streptococci are specifically defined. These bacteria are classified based on their shapes, which can include coccus (spherical), bacillus (rod-shaped), and spirillum (spiral-shaped).
When referring to streptococci, we are mentioning a specific type of spherical-shaped bacteria that often arrange themselves in chains.
This arrangement is not just due to their shape but is also a product of their pattern of growth and division. Therefore, the correct answer for the shape and form of streptococci would be both round-shaped and chain-shaped.
The correct option is d.