How could using a video best extend information from the interview when birds get flu and cows go mad! how safe are we? .
the video could show what dr. dowell does at work.
the video could state what dr. dowell does for work.
the video could tell when dr. dowell goes to work.
the video could explain dr. dowell’s interest in his work.

a). in this case, dh> 0 and sd> 0. if t becomes larger, the term "-tds" will become more negative. at some point, it is possible that -dts will be more negative than the dh is positive, and the reaction will become spontaneous. this is probably the correct answer, but you should look at all of the other possibilities and make sure of that.