Answer:
Many were killed by Japanese soldiers.
Step-by-step explanation:
The passage talks about hard conditions that prisoners had to endure from Japanese soldiers as well as through the march. The author explains how they were beaten up by the Japanese, and some were severely injured and broken.
The weather was harsh, so prisoners were struggling in the sun. The Japanese continued to beat them.
He finally said that he mostly fought for survival and tried to carry on in order to live. This implies that many of the people who were with him died as a consequence of terrible conditions and the beatings of the Japanese. That is how we can finally conclude that Japanese soldiers have killed many of the prisoners and that is what is explained indirectly in the passage.