已知等差数列$\left\{a_n\right\}$的前n项和为$s_n$，若$a_1+a_2=5$，$a_3+a_4=9$，则$s_{10}$为（     ）

如图所示，质量不等的木块A和B的质量分别为m₁和m₂，置于光滑的水平面上．当水平力F作用于左端A上，两物体一起做匀加速运动时，A、B间作用力大小为F₁．当水平力F作用于右端B上，两物体一起做匀加速运动时，A、B间作用力大小为F₂，在两次作用过程中（　　）

阅读下列短文,从每小题所给的A、B、C、D四个选项中选出一个最佳选项。

    Tu Youyou, aged 85, is a medical scientist at the China Academy of Traditional Chinese Medicine. she has just become the first Chinese woman to win a Nobel prize, for helping discover artemisinin, a new kind of medicine known as "Qing-hao-su" in Chinese in 1971 and dihydroartemisinin, used also to treat malaria(疟疾).

    The discovery of “Qing-hao-su” and its use in treating malaria are regarded as the most important breakthrough(突破) in tropical medicine in the 20th century. It is also a major health improvement for people in developing tropical countries in south Asia, Africa, and South America.

    This is the first time her work has been widely recognized in China, and it also marks the first time China has won a Nobel prize in the sciences.The last time a Chinese national won a Nobel Prize was in 2012, when Mo Yan got the literature award.

    Tu also received several medical awards in the past including the 2011 Lasker Award in Clinical Medicine for the same achievements.Tu was the first native Chinese who was educated and works in China to win the Lasker award, too.