What are the problems with Lamarck’s theory of evolution?

One-two paragraphs, APA format and please provide references. (Discussions due Tuesday) (1)Jean-Baptiste Lamarck believed that physical diversity among animals could be explained by physical stressors experienced by one generation being passed on to the next. Giraffes, therefore, have long necks because one giraffe, a long time ago, had to stretch out and reach for food, and this characteristic was passed on to its offspring.What are the problems with Lamarck’s theory of evolution?