Why do I see many mongod processes running?

I am running a single MongoDB database. No sharding. When I run htop, I see a lot of instances of mongod. Is that normal? Does every connection create a separate mongod process? Should I be concerned?

For some reason when I use top, only one of them is shown. That part is confusing also.

As asked in the comments, output of "ps axjf | grep mongod":

12858 12878 12877 12858 pts/0    12877 S+     500   0:00              \_ grep mongod
1  2691  2690  2690 ?           -1 Sl     497  70:54 /usr/bin/mongod -f /etc/mongod.conf

Duplicate .. htop is showing different threads as well. not just processes. top and ps show only processes.