Why are cell walls present in plant cells but absent in animal cells

What's the waste product of electrons and pyruvate combining in fermentation?  

Tay-sachs disease is caused by a mutation in the hexa gene located on chromosome 15. tay-sachs follows an autosomal recessive pattern of inheritance. with the of the diagram, identify which of the offspring will be an unaffected carrier. a diagram showing the genes of parents who are carriers of tay-sachs disease a. a, b, and c b. b and c c. a and d d. a e. d

Why do the circulatory systems of land vertebrates have separate circuits to the lungs and to the rest of the body?