College/University admission essay for BioChem major

Write an 250-250 words paragraph essay for EACH prompt, 3 in total. 
1.Describe an example of your leadership experience in which you have positively influeneced others, helped resolve disputes, or contribute to group efforts overtime.
2.What would you say is your greatest talent or skill? How have you developed and demonstrated that talent over time?
3.Describe the most significant challenge you have faced and the steps you have taken to overcome this challenge. How has this challenge affected your academic achivement?
Noted: This is the college admission essay for bio chem major. I am an immigrant and also a very hard-working individual. I work very hard to have good grades in school. I once cooperate with NASA in their academy project. I volunteer as a tutor and help other students. Please write my essay according to these information. Thank you so much!