Answer:
open-source
Explanation:
open-souce software allows any user to submit modifications of the source code
Answer:It will decrease harmful emissions, so the factories will no longer need to install them.
Explanation:
This helps improve the safety of the surrounding community and workers. But this technology is expensive and required time and effort to install.
Answer:to add a column to existing table.
to rename any existing column.
to change datatype of any column or to modify its size.
to drop a column from the table.
Explanation:
hope this help