An experimental Ebola drug healed all 18 monkeys infected with the deadly virus in a study, \_17\_ hopes that the treatment might help fight the outbreak raging through west Africa — once more of it can be made. The monkeys were given the drug, ZMapp, three to five days after they were infected with the virus and when most were showing symptoms. It is not known how well the drug would work in people, who can take up to 21 days to show symptoms and are not infected \_18\_ the lab monkeys were. Several experts said it is not possible to \_19\_ a window of opportunity for treating people, but that it was encouraging that the animals \_20\_ when treated even after advanced disease developed. There is an app for everything these days. You have a mobile app for waking you up in the morning to one that lets you play music from your favorite play store, read the news and watch the latest TV serials. But what is it that makes an app truly great and keep users from removing it from their devices later on? The \_21\_ for developers who create these apps is pretty fierce. Studies show an app that doesn't keep users interested would be \_22\_ within the first three days. It is important to understand that people share things which evoke positive emotion or provide them with good experiences. A mobile app that offers value is also likely to be recommended by a friend or acquaintance more. If you want your app to be shared a lot after \_23\_, ask yourself some questions: Does your app offer something your target audience will like? Does it have anything worth sharing? You also need to avoid \_24\_ your users by giving them unnecessary features, advertisements, or untimely push notifications. Another important tip is always to test your app on real users, which can help you pinpoint annoyances and use them as a basis to improve your product. Anything from connectivity to navigation that makes users experience inconvenience in any way is a \_25\_. How successful your product is depends on your users. You need to look out for anything that might prompt users to abandon your app.