【简答题】SECTION B Directions ; For each blank in the following passage there are four words of phrases marked with A, B, C and D. Fill in each blank with a word that best fits the context. This is a true stor...
【多选题】Complete the following sentence accurately, explaining your reason for accepting or rejecting each of the four phrases (more than one can be correct). The role of calcium in muscle contraction is:
A.
T o detach myosin heads from actin.
B.
T o spread the action potential from the plasma membrane to the contractile machinery.
C.
T o bind to troponin, cause it to move tropomyosin, and thereby expose actin filaments to myosin heads.
D.
T o maintain the structure of the myosin filament. heads.
【单选题】Choose one from the four words of phrases which cannot explain the underlined part of the senence. Another concern is that the Internet and social networking sites like Facebook make it possible to in...