If you know that the renal clearance of substance x is zero, which of the following can you say is true about how the kidney handels x?
a. x is filtered, not reabsorbed, and additional is secreted
b. x is either not filetered or filtered and completely reabsorbed
c. x is not filtered
d. x is filtered and completely reabsorbed
e. x is filtered, not reabsorbed, not secreted

The oxidizing agent our bodies use to obtain energy from food is oxygen (from the air). if you breathe 15 times a minute (at rest), taking in and exhaling 0.5 l of air with each breath, what volume of air do you breathe each day? air is 21% oxygen by volume. what volume of oxygen do you breathe each day?

Talking listening and reacting non verbally are all part of communicating

Which is an advantage of having memory cells when a pathogen is encountered for a second time. a) the memory cells are what proliferate into clones of cells in response to the binding of an antigen. b) memory cells are vital to the primary immune response in that they immediately recognize pathogens even at the first encounter. c) memory cells are essentially effector cells that are short lived and attack antigens even without having a receptor specific to that antigen. d) it ensures that more lymphocytes with a receptor specific to a particular antigen will be present than in a host that had never encountered that pathogen.