Why is it plant cells have cell walls and animal cells do not?

Plant cells have cell walls around them, and animal cells don't have cell walls.The cell walls give plant cells their boxy shapes. ... That's nice for plants, because it gives them the ability to grow up and out, where they can get lots of sunlight for making their food

not necessarily. higher fitness requires the organism to be reproductive successful. for example, an organism at age 10 with 15 offspring is much more fit than an organism at age 15 with only 5 offspring.