Please write a introduction and a conclusion about these articles! I need the introduction to be eight sentences long and the conclusion to be six sentences long

1. Guarana (Paullinia Cupana), a plant native to the Amazon basin, has garnered attention for its potential ergogenic effects due to its caffeine content.
2. Jones, L., Johnstone, I., Day, C., Le Marquer, S., & Hulton, A. T. (2021). The Dose-Effects of Caffeine on Lower Body Maximal Strength, Muscular Endurance, and Rating of Perceived Exertion in Strength-Trained Females. Nutrients, 13(10), 3342.https://doi.org/10.3390/nu13103342
3. Filip-Stachnik, A., Krzysztofik, M., Kaszuba, M., Leoska-Duniec, A., Czarny, W., Del Coso, J., & Wilk, M. (2020). Placebo effect of caffeine on maximal strength and strength endurance in healthy recreationally trained women habituated to caffeine. Nutrients, 12(12), 3813.https://doi.org/10.3390/nu12123813
4. Effects of caffeine and sex on muscle performance and delayed-onset muscle soreness after exercise-induced muscle damage: a double-blind randomized trial https://journals.physiology.org/doi/full/10.1152/japplphysiol.01108.2018
5. Effect of caffeine ingestion on one-repetition maximum muscular strength https://doi.org/10.1007/s00421-007-0557-x
6. Crowe, Melissa J., Anthony S. Leicht, and Warwick L. Spinks. "Physiological and Cognitive Responses to Caffeine During Repeated, High-Intensity Exercise."International Journal of Sport Nutrition & Exercise Metabolism 16, no. 5 (October 2006): 528-44.
7. Filip-Stachnik, Aleksandra, Michal Krzysztofik, Magdalena Kaszuba, Agata Leoska-Duniec, Wojciech Czarny, Juan Del Coso, and Michal Wilk. "Placebo Effect of Caffeine on Maximal Strength and Strength Endurance in Healthy Recreationally Trained Women Habituated to Caffeine."Nutrients 12, no. 12 (December 2020): 3813.https://doi.org/10.3390/nu12123813.
8. Goldstein, Erica, Patrick L. Jacobs, Michael Whitehurst, Tina Penhollow, and Jose Antonio. "Caffeine Enhances Upper Body Strength in Resistance-Trained Women."Journal of the International Society of Sports Nutrition 7, no. 1 (May 14, 2010): 18.https://doi.org/10.1186/1550-2783-7-18.