18.04 – python version (conda -forge)

I am using 18.04 Ubuntu with Anaconda.Recently i have trying to install OpenCV through conda-forge channel in the base environment. I did not install purposely any Python version and did not use any pip command either in base environment. Now, in the base environment, if execute just python, i get the same python version as system version and if execute python3 , i get the version installed by conda-forge. Please refer the screen shot.Python_on_Conda_base

I would like to know what is difference between python and python3 command? or what is advantage having this 2 version.What is should i keep in mind? basically i prefer the version 3.7.5 Python
So far,i did not face any ssue, but removed the conda-forge channel from Anaconda.

Cheers!
Chandra