.
What does "this" refer to? Choose the idea that completes the sentence.
This leg was specifically designed for rock climbing and has
many features that can help the climber, such as the spiked
foot, which grips the rock face better than any biological foot
could. Other prosthetics can help people excel at the sports
they love, too.
Engineer Hugh Herr has made this his life's work.
Engineer Hugh Herr has made
his life's work.
teaching rock climbing
designing prosthetic limbs
strengthening biological limbs
1) discovering challenging rock faces

designing prosthetic limbs

Explanation:

this is because the first line of the image says that it was designed, and the 4th line practically tells us that it was the prosthetic that was designed, and then the last line says that Engineer Hugh Herr has made this his life's work which means designing prosthetic limbs is what he has made his life's work

1. read the following excerpt from franklin d. roosevelt's "fireside chat 19":

on the other side of the picture, we must learn also to know that guerilla warfare against the germans in, let us say serbia or norway, us; that a successful russian offensive against the germans us; and that british successes on land or sea in any part of the world strengthen our hands.

remember always that germany and italy, regardless of any formal declaration of war, consider themselves at war with the united states at this moment just as much as they consider themselves at war with britain or russia. and germany puts all the other republics of the americas into the same category of enemies. the people of our sister republics of this hemisphere can be honored by that fact.  

the true goal we seek is far above and beyond the ugly field of battle. when we resort to force, as now we must, we are determined that this force shall be directed toward ultimate good as well as against immediate evil. we americans are not destroyers — we are builders.

analyze the effectiveness of this excerpt. how does it function within the speech as a whole? how does the structure of the excerpt to convey the speech's purpose and key points? support your argument with evidence from the speech. (10 points)

reasoning from several particular examples to establish a general principle