题干

将酵母菌培养液进行离心处理。把沉淀的酵母菌破碎后,再次离心处理为只含有酵母菌细胞质基质的上清液和只含有酵母菌细胞器的沉淀物两部分,与未离心处理过的酵母菌培养液分别放入甲、乙、丙三个试管中,并向这三个试管内同时滴入等量、等浓度的葡萄糖溶液。在有氧的条件下,最终能通过细胞呼吸产生的CO2和H2O的试管是(  )

A:甲

B:丙

C:甲和乙

D:丙和乙

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B

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    Across Britain, burnt toast will be served to mothers in bed  this morning as older sons and daughters to deliver their supermarket bunches of flowers, But, according to a new study, we should be placing a higher value on motherhood all year.

    Mothers have long known that their home worked was just heavy as paid work. Now, the new study has shown that if they were paid for their parental labors, they would earn as much as£172,000 a year.

    The study looked at the range of jobs mothers do, as well as the hours they are working, to determine the figure. This would make their yearly income £30, 000 more than the Prime Minister earns.

    By analyzing the numbers, it found the average mother works 119 hours a week,40 of which would usually be paid at a standard rate 79 hours as overtime. After questioning 1,000 mothers with children under 18,it found that ,on most days, mums started their routine work at 7am and finished at around 11pm.

    To calculate just how much mothers would earn from that labor, it suggested some of the roles that mums could take on, including housekeeper, part-time lawyer, personal trainer and entertainer. Being a part-time lawyer, at £48.98 an hour, would prove to be the most profitable of the “mum jibs”, with psychologist(心理学家)a close second.

    It also asked mothers about the challenges they face, with 80 percent making emotional(情感的)emand as the hardest thing about motherhood.

Over a third of mums felt they needed more training and around half said they missed going out with friends.

    The study shoes mothers matter all year long and not just on, Mother's Day. The emotional, physical and mental energy mothers devote to their children can be never-ending, but children are also sources of great joy and happiness. Investing(投入)in time for parenting and raising relationships is money well spent.