Within the trachea, the contains mucous glands that secrete mucus onto the epithelial surface through secretory ducts.

The correct answer is a. we know this because n (hap) + n (hap) = 2n (dip).

To wear the full equipment.

Ithink sanforcisco california (i am not 100% sure) if you feel the opposite so that lol

Iam not sure but to me it with be a or dsorry if i was late! hope this ! : )if you really want me to find out the answer that is correct tell me and i will do more research but the a or d makes sense to me.