优生学

优 = 亻 + 尤 : Rosa Luxemburg (亻) and Maud Younger (y) are awarding each other medals (尤) for being superior (优) than the rest of the world in front of the outhouse (ou1).

优 = 亻 + 尤 : A disabled man is lying on the streets, his crutches nearby. He's blaming (尤) everyone for not helping him. Finally, a man (亻) of excellent reputation comes to his aid.

生 = 牛 + 一 : Mnemonic symbol: a cradle.

Sherlock Holmes (sh) comforts a crying baby bull (牛) in a cradle (生) in front of the engine ((e)ng1) and plays him a tune on a flute (一).

学 = 小 + 冖 + 子 : Xu Xian wants to study scienceology and learn more about daisies. Just inside the elevator's kitchen, he put some daisies into a prize cup and covered them with a cooking top. He wants to study the growth rate of the daisies depending on the pH of the water in the prize cup.