凝乳酶能催化乳汁凝固，常用于奶酪的生产．为探究温度对凝乳酶活性的影响，某同学设计了如下实验：

①取若干试管，分为A、B、C、D、E、F六组，每组两支试管，其中一支试管放入2mL凝乳酶，另一支放入2mL乳汁．

②将六组试管分别置于不同温度水浴15min．

③将每组试管中的凝乳酶和乳汁混合后在原温度下继续水浴，记录凝乳所需时间，结果如下表．

请回答问题：

（1）上述实验结果中，凝乳所需要的时间越短，表明酶的活性越____ 

（2）A组中乳汁不凝固的原因是____ ．F组中乳汁也不凝固，若将其温度冷却至40℃，乳汁将____（会、不会）凝固，原因是____ 

（3）通过以上实验，____（能、不能）得出“凝乳酶的最适温度是40℃”的结论．

阅读下面材料， 在空白处填入适当的内容(1个单词)或括号内单词的正确形式。

    Brighton is the____ (health)city in Britain with the highest level of personal trainers, yoga clubs and health food stores, according to a survey related on Friday.

    The survey, ____ looks at 19 statistics covering health, ____ （fit）and environment, says Brighton has the highest number of residents ____ (eat) at least five kinds of fruit and vegetables a day.

    The survey, ____ (conduct) for the Sky Travel channel, has compared 15 cities across the UK. It says Brighton residents live ____ an average age of 78 years old. They are twice as likely ____ (walk) or cycle to work as the people living in other parts of Britain.

    In ____ （compare）with the national average, Brighton has nearly a third more health food stores and personal trainers than____ in any other city in Britain. It has twice many yoga clubs, and the level of fat residents is below the national average.

    Meanwhile, ____ survey also finds that Brighton residents have the best levels of cholesterol (胆固醇) and blood pressure in Britain.

 实验测得0.5kg某物质温度随时间变化的图象如图示，已知物质在固态下的比热容为C₁=2.1×10³J/（kg℃）．假设这种物质从热源吸热的功率恒定不变，根据图象解答下列问题：

（1）在最初的 2min内，物质吸收的热量为多少？(1分)
（2）求该物质在液态下的比热容C₂。
（3）若规定“质量为1Kg的某种晶体物质在完全熔化时所吸收的热量叫做这种物质的熔化热” 用“λ”表示，根据图像信息，计算该物质的熔化热。