Since you haven't attached any options, I will explain the basics and properties of surface tension.
Surface tension is in its simplest form, is the force that causes the cohesive molecules of a liquid to join together and form a conjoined layer, allowing it to resist an external force. This is commonly seen in an experiment with a penny and a water dropper. For this experiment, simply create a hypothesis of how many drops you think would fit on a penny. Test your hypothesis and observe the results. You will see that often the amount of drops are underestimated and many more fit on the coin. While on coin, drops form a small parabolic shape on the penny, with the drops holding on tightly against each other.