Final answer:
Maconochie had trouble gaining support for his mark system due to disagreement with his concept of task sentencing, belief in harsh punishment, preference for cruel conditions, and complexities of the system.
Step-by-step explanation:
The mark system developed by Maconochie faced significant challenges in gaining support for several reasons. Firstly, most people did not agree with his concept of task sentencing over time sentencing, as they believed in harsh punishment as the only way to reform prisoners. Additionally, some people believed that cruel conditions were more effective. Lastly, many people found Maconochie's marks system too complicated and difficult to implement.