题干

分析有关科学探究的资料,回答问题.

盐酸普萘洛尔和肾上腺素都可以影响心脏的活动.普萘洛尔是治疗心律失常、心绞痛、高血压等常见心脑血管疾病的常见药物,可减慢心率,抑制心脏收缩力与传导、循环血量减少、心肌耗氧量降低.现用盐酸普萘洛尔和肾上腺素开展有关的实验研究.

实验目的:探究盐酸普萘洛尔和肾上腺素对小鼠耗氧量的影响

材料用具:小鼠若干只、注射器、检测耗氧量装置(如图1)、生理盐水、肾上腺素溶液和盐酸普萘洛尔溶液(均用生理盐水配制).

方法步骤:


结果分析:

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    Children in the United States eat too much pizza that some researchers now argue the food should join the ranks of sugary drinks and fast food for the harm they do to health.

    In a new study, the researchers found that pizza is a large source of calories, saturated fat(饱和脂肪)and salt in children's diets.Children should not eat more than two slices of pizza for a meal,and should pair that with salad, rather than with another high-calorie food,the researchers concluded.

    “Parents should aim to control pizza consumption(消费), particularly as a snack where it was shown to have a very adverse impact on children, and they should put their pizza dollars toward healthier brands.”Said Lisa Powel, director of the Illinois Prevention Research Center.

    Pizza has become a matter of focus in recent years for researchers who look at the meals children eat, rather than the nutrients within them.Studies have found pizza is among the greatest sources of calories for children.

    “Since pizza remains a common part of children's diet, we need to make 'healthy' pizza.”Powel said.To make pizza healthier, food producers should reduce its saturated fat and salt, and increase its whole grain content,” she said.

    Whether or not pizza is harmful enough to be picked out as an unhealthy food, the study attracts attention to a larger issue with the modern American lifestyle, said Alexis Tindall, who was not involved in the flow research. “Many foods are eaten too frequently and in large sizes,” said Tindall.To solve the problem, people don't have to give up eating pizza, but instead, they can eat smaller and healthier pizza,”she said.

    “Make it at home, instead of ordering it out where you don't have any control over how it's made.” Tindall said. “When we make it at home, we can choose healthier ingredients,increase the vegetables, reduce fat, and put in less cheese.Pizza doesn't have to be just pepperoni(意大利辣香肠)and cheese.”