Final answer:
Cameras and film becoming able to capture images led to a. people becoming popular photography subjects, as it allowed for the recording of people's likenesses and lives.
Step-by-step explanation:
a. People became the most popular photography subject when cameras and film were able to capture images because it allowed for the recording of the likenesses of ourselves and our loved ones.
Portrait photography gave rise to commercial photographic studios and became a way for people to document their lives and relationships. With the advent of digital photography and the popularity of selfies, people's lives have continued to be popular subjects for photography.