's conversation view
groups email messages sharing the same subject into single conversation threads. This display keeps your mail folder neat and organized.
is enabled by default. But if don't want to take advantage of this feature, you can disable it in your account settings.
How To Ungroup Messages in a Gmail Conversation
Sign in to Gmail
and click on the Cog
icon > Settings
> Conversation View
. Then select Conversation view off
Click on Save Changes