validity of regression assumptions on residual plot

I am learning regression course.For a homework given the residual plot I have to analyze it.This is how I interpreted it.I want to know if there are any wrong interpretations.
1)Since the variability at each x is not the same,there is non constant variance.
2)The residuals are not randomly scattered as a grouping of some kind can be seen and therefore the assumption on residuals are independent is violated.
3)Since the residuals are scattered around 0 it can be concluded that the mean of the residuals is 0.
The residual plot is attached.
Please help me to interpret this