The push or pull of an object is called --. a. energy b. force c. work d. matter

Here are the answers to your questions:

19. The push or pull of an object is called force. The correct option is $\boxed{\text{B. force}}$

20. The main source of light to the Earth is the Sun. The correct option is $\boxed{\text{B. Sun}}$

21. The symbol $\boxed{=}$ is a battery. The correct option is $\boxed{\text{B. battery}}$

22. The best method of separating sand and water is Filtration. The correct option is $\boxed{\text{D. Filtration}}$

23. The closest planet to the Sun is Mercury. The correct option is $\boxed{\text{C. mercury}}$

24. The hottest planet in our solar system is Venus. The correct option is $\boxed{\text{C. Venus}}$

25. Dirty water can breed the following except crocodiles. The correct option is $\boxed{\text{A. crocodiles}}$

26. The following diseases are caused by using unsafe water except ectopic. The correct option is $\boxed{\text{A. ectopic}}$

27. The seed cannot germinate without the presence of warmth and water. True. The correct option is $\boxed{\text{A. True}}$

28. The following are examples of habitats except Stone. The correct option is $\boxed{\text{A. Stone}}$

29. We have 8 planets now. The correct option is $\boxed{\text{A. 8}}$

30. Gas exchange occurs in plants through the Stomata. The correct option is $\boxed{\text{A. Stomata}}$