Biology - Genetics

In another species, a bell shaped, red flowered plant was crossed with a tube shaped, white flowered plant of the same species. One of these f1 plants was crossed with another bell shaped, white flowered plant of unknown breeding behaviour. The following offspring were obtained: 97 plants eith pink bell shaped flowers;99 plants with white bell shaped flowers; 33 plants with pink tube flowers; 31 plants with white tube flowers. Explain these results as fully as you can. 

(20 marks)