Crossing over is a method of (blank)?

Can someone i have no idea of how to do this.

3. in the fruit fly, recessive mutation brown, b, causes brown color of the eye and absence of red pigment. recessive mutation p of another independent gene causes purple color of the eye and absence of brown pigment. the cross of a brown-eyed female and purple-eyed male produced wild type eyes. what will be the colors and their ratio in f2?

There are two tomato plantlets one of them is kept in an oxygen chamber with a light source and another is kept in sunlight. both of them are watered regularly what will be the observation after two weeks