Mr. Barlow, I will refer you to page 30 of Bosc and Gagnon, which identifies that the responsibility is to the minister to answer questions appropriately and to call on officials as appropriate to do so. If you ask a question of her, it's discourteous not to let her answer.
I'll stop your time briefly, but the minister has asked Dr. Tam to respond to your question, so I will invite Dr. Tam to do so.