Undergraduate / Science Olympiad / Teaching position in China - EXTRACURRICULAR ESSAY--Which one? [5]

I think if you add more information about how you deal with the difference between you and those Chinese kids, the second one would be better since it is about cultural collide.

Undergraduate / "Optional" Why Duke? Short Answer: Undergraduate Economics [9]

First, the answer is a bit of short. You should fully utilize the given words limit. Second, your answer is too general. There are tons of schools provide both Finance and Economics. What make Duke a different one? Do thorough research, or just let it go. It is optional anyway

Undergraduate / Running on our school's track every night; Rice short answer [7]

The 150 words activity essay. Please tell me which one is better?
Any comments will be appreciated!
I had seldom climbed mountains without stairs before I participated in the Arctic Expedition one year ago. Staring at the steep mountain covered with snow, I had never felt so hesitated whether I accepted the challenge or just waited at the bottom as our guide suggested. With a hope of not regretting for myself, I plucked up to join the climbing team. As I climbing higher, I felt dizzy and fell down for several times. The pain and exhaustion drove me to go back to the foot, but another voice that I should persevere my original choice even facing the difficulty impelled me to keep climbing. Finally, I got to the top of the mountain and heard the Arctic song which as if was telling me that nothing is insurmountable as long as I try hard. The only thing to overcome is my fear.

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Running on our school's track every night after the self-study period, I enjoy myself as a free spirit. Nothing would interrupt me. I am able to reflect what I have done today and plan for the upcoming day, or I will just let my mind go blank, releasing all the pressure and refreshing myself with each out breath, or sometimes I simply want to feel the physical exhaustion which will give me a sense of existence.

I run no matter the weather. I run no matter the season. It is a way to let me feel the change of the environment, such as temperature, humidity, wind, smell of the grass. Running enables me to detect the miniscule details in life.

Every time when I am tired, I tell myself "One meter more." , because I love pushing my limits and then realize there is no limits if I myself do not set them.