Hi Fariha,
Comment(<!-- -->) is not required to code.
Your activities below:
{{#each contact.activitypointer_contact_regardingobjectid}}
- Activity Name: {{this.subject}} Due Date: {{this.scheduledend}}
{{/each}}

In addition, I would like to share some experiences for dynamic expression:
1. DE could only support to retrieve entities that have direct relationship to contact,
in other word, we could only use relationships in assist-edit drop down list.
2. Some fields type such as:
Lookup: it will display related entity's record id instead of its name.
Date and time: it will display both date and time.(as in my screenshots).
-> You need a workflow to sync data from original field to custom field and convert data to formatted value.
Currency: it will only display number without symbol.
-> You should add symbol manually in HTML.
Regards,
Clofly