Final answer:
The secondary droplets that break free from the main blood drop during an injury are called satellite droplets. They can help in forensic investigations to determine the direction and force of blood impact. Therefore, the correct option is B.
Step-by-step explanation:
When an injury occurs and a blood vessel is severed, not only does blood leak out, but various blood components such as erythrocytes (red blood cells) and leukocytes (white blood cells) can also escape through these openings. During the formation of a bloodstain, the secondary droplets that break free from the edge of the primary, or main, blood drop are known as satellite droplets. They can provide important information in forensic investigations, helping to determine the direction from which the blood came and the amount of force involved in its impact.