The answer would be: C) sexual selection.
Sexual selection happens where one of the individuals choose the partner to sex based on some criteria. In this case, the ability to have a beautiful bower will determinate the ability of the bird to have sex and produce offspring. The criteria are not limited to visual. It could be diverse in other cases, like a deeper croak in frog
Salt is a solid by itself. With water, it forms a liquid.
Answer:
19. B a force continues to be applied to the object.
20. B massive force.
21. B inertia
22. C unbalanced force.
23. C friction
24. A balanced
25. C an outside force acts on it
26. B an equal and opposite reaction
27. A No, they are traveling in different directions.
28. A No, because the direction is different
29. A force
30. D Gravity