Point well taken on the parallelism, reachac.

Thanks.

I think the answer is 1 Can rearrange the eqn to 7^(11*13*16*19*21) Units digit of 7^n will repeat 7,9,3,1 with 7 or 3 on odd powers and 9 or 1 on even powers. We know it will be an even power since 16 is a factor (can narrow the ans down to 9 or 1) Units digit should be 1 since the factor 16 tells ...

Right but the problem asks for REMAINDERS of 1 when divided by 3. So if we go back to the general eqn for a number of N=QD+r and rearrange to express as N/D=Q+D/D we find that 1=0*3+r (r=1) or to rearrange in other form of 1 divided by 3 --> 1/3 = 0 + 1/3....you can see you get a remainder of 1 N=nu...

E seems properly parallel

animal "that is found...and that..has shimmering metallic colors"

C is better than D because

"is" agrees with "detrimental" and "include" agrees with "effects"

"yet" is the conjunction needed to convey the logical contrast vs. expectations that a bag that large must also be very heavy

I think B also changes the meaning. The churches are not actually standing there putting on a presentation showing how wooden buildings can last indefinitely. A more clearly gets the point across.