用于温室气体浓度观测的“呼吸”号卫星于2009年1月21日在日本种子岛宇航中心发射升空。该卫星装备了高精度的观测设备，将利用二氧化碳和甲烷等温室气体吸收特定波长辐射的特点，通过观测地表反射的能量变化来推算温室气体的浓度。该过程主要利用了（    ）。

【历史变迁】

70年代末我国实行计划生育政策，提倡少生优生，有效地控制了人口过快增长；近年来，由于养育子女的成本大幅提升及生育观念的改变，新出生人口的减少加剧了我国老龄化进程，需要再次调整人口政策。

【现实需要】

人口政策与经济、社会发展密切相关，新出生人口减少， “人口红利”已逐步消失，社会有效需求不足，制约经济社会发展，必须调整人口政策。

根据短文内容，选择最佳答案。

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在进行有性生殖时，亲代的基因传递给子代的“桥梁”是（　　）