Which type of cell is part of adaptive immunity?

What cell is responsible for releasing free antibodies into the bloodstream?

The human immune system includes several types of specialized cells whose role is to eliminate invaders threatening the health of the body.

A certain immune cell has a certain type of antibody on its surface. When it comes in contact with a pathogen (attacker) that matches its antibodies, the immune cell signals other immune cells to attack the invader and produces more antibodies in order to flag other invaders of the same type. What type of cell is this immune cell?

Which of the following cells of the immune system release antibodies into the bloodstream?

If you are fighting an active infection, chances are __________.

Which of the following are long-lived and provide future immunity against a second invasion by the same antigen?