Hi, please help me with this!

(a) How does backward selection conduct variable selection? List also two of its drawbacks. (3p) (b) Why is simply picking the model which gives the largest value of R2 not a good idea with respect to variable selection? (1p) (c) The following plot shows the LASSO coeicient proles in a regression problem with a response variable 3.5- and the explanatory variables .17,:1!,-2, 17,13, 3:\