Effect on the minimum distance of a code if we remove some rows/ column in its matrices

Question

Suppose you are given a linear code with generator matrix $G$ and parity check matrix $H$. The following is a list of ways you might modify your code. For each, determine the possible effect on the minimum distance.

1. Remove a row from $G$.

2. Remove a row from $H$.

3. Remove a column from $G$.

4. Perform elementary row operations on $H$.

My understanding is that:

1. Removing a row from $G$ --> reducing the dimension $k$ --> possibly increase/decrease the min distance, but not sure if increasing or decreasing.
2. Same as 1
3. Removing a column from $G$ --> decreasing the length $n$ of the codewords --> decreasing the weight of codewords --> decreasing min distance $d$.
4. Performing elementary row operations on $H$ --> we get the equivalent $H'$ --> nothing changes --> not affecting the min distance.

Can anyone please point out if I am wrong or add more comments? Thanks.