Question

please answer all the questions
I will mark as best​

Answer 1

13. placenta

14.oestrogen and progesterone

16.the reaction in which an base is reacted with acid to neutralise it

18.properties of elements are the periodic functions of their atomic mass

19. a.mercury

that's all...sorry for incomplete answer

but still..it may help

Answer 2

19 .b . graphite .

22. 1.incidence ray, normal ray, reflected ray lay on same plain .

2. angle of incidence is equal to angle of reflection .