Microeconomics homework

Envision two products (A and B) that are considered substitutes for one another. and that both are traded in perfectly competitive markets.  Envision further that the demand for Product A increases.  In a total of 75-150 words, please address the following questions.  In the long run,

1.       What rate of return will firms in the market for A earn?  Why?

2.       What rate of return will firms in the market for B earn?  Why?

3.       How will the market for A have changed as a result of the increased demand for A?

4.       How will the market for B have changed as a result of the increased demand for A?

Response questions from 1 to 4 in 75-150 words. Looking forward to receiving full points on this assignment.