During the knee replacement surgery, cartilage and bone that are causing the patient pain will be replaced with the new knee replacement implant. the knee replacement implant will replace both the top and the bottom parts of the knee joint. the average age of a patient needing knee replacement surgery is about 70 years.

which two criteria should the doctors be considering as they develop their knee replacement implant design?
a.
the design should chemically react with the surrounding leg bone, and it should be able to bend.
b.
the design should be strong enough to support the patient's weight, and it should be able to bend.
c.
the design needs to be able to grow as the body grows, and it should lock into place to support the body.
d.
the design should break down quickly in the body, and it should lock into place to support the body.