He asserted his opinion.

This project requires local procurement.

We conducted a field survey and procured the necessary materials on site.

What are the raw materials for this recipe?

He affirmed with full confidence.

He confidently affirmed that the plan would succeed.

This antigen triggers a specific immune response.

This vaccine contains the antigen of the new coronavirus.

Calls for tax reduction are growing.

We need to find new ways to reduce energy use.