is necessary

This system did so at a rate almost four times what is necessary to be deemed a bomb cyclone, officials said.

City employees may not seek or collect information about an individual’s citizenship or immigration status, unless the information is necessary to provide a city service.

I know I’m repeating these words, small and weak, but it is necessary.

"Long-term action is necessary to deliver a sustained reduction to the prison population and support the effective functioning of prisons," she said.

However, even though it is necessary to maintain cell functions, oxygen also causes oxidative stress by forming free radicals, reactive molecules that endanger the cell.