A person who has allergies has a compromised immune system because the body’s immune system: OVEREACTS TO AN ANTIGEN
<span>That is known as PDA.
PDA - Patent ducts arteriosus. PDA is a condition in which the ducts arteriosus does not close. The word "patent" means open. The ducts arteriosus is a blood vessel that allows blood to go around the baby's lungs before birth.</span>
Answer:
The battery is the set of vertical lines at the bottom, so there's one battery.
The switches are the line between the small circles (they're closed here) there are 2 of them.
The circles with Xs inside are bulbs.
So B is correct.
