题目

4 Study and Homework Apps for Android!BrainlyPrice：Free/$15 per 3 months/$24 per yearBrainly is a social network for learners. You sign up, ask questions, and get answers (usually).Additionally, you can browse the site, answer other people's questions, and help them out as well. There They charge on a quarter basis ($15)or a yearly basis($24).ForestPrice: Free/Up to $1.99Forest is a different type of app. One of the biggest distractions during study is your smartphone.Forest helps put a stop to that. You open the app and a tree grows, The tree dies if you leave the app.Thus, there is a littl等质量的稀硫酸分别与足量的镁、铁、锌三种金属反应，下列图像能正确生产氢气质量与反应时间之间关系的是  (    )