Which of the following statements is true about the bicarbonate buffer system?
a. bicarbonate ions accept hydrogen ions if conditions are too basic.
b. carbonic acid acts like a base when it releases the hydrogen ion in basic condition
c. in extremely acidic conditions, carbonic acid will act like an acid and release hydrogen ions to lower the ph.
d. bicarbonate ions act like a base in that they combine with hydrogen ions to increase the ph in extremely acidic conditions.

Name the bone/structure/process that fits the following description: a) a bone with a complex shape. b) found in the medullary cavity. c) a large, rough process. d) it is thin, like a plate. e) shaft of a long bone. f) a mature bone cell. g) a large, round, smooth process. h) it covers outer surface of bone. i) a shallow depression on surface of bone. j) a roughly cube-shaped bone. k) the covering of epiphysis. l) a very narrow ridge of bone. m) space between lamellae for an osteocyte. n) chamber within diaphysis o) also called wormian bone. p) it secretes new matrix. q) end of a long bone. r) a small, round hole. s) a matrix, arrangement in spongy bone. t) it is a chamber within a bone. u) a network allowing osteocytes to receive nutrients. v) one example is the patella. w) it houses artery, vein and nerve. x) almost flat, smooth surface of a bone. y) a narrow, pointed process.