Critical Reasoning (CR) | Re: Networks of blood vessels in bats’ wings serve only to dispe

If we negate (E) - Heat generated by Sandactylus in flaping its wings in flight could have been dispersed by things other than the blood vessels in its wings. It does not invalidate our conclusion. However, if we negate (A), it reads Sandactylus would have had networks of blood vessels in the skin of its wings if these networks were of no
use of to Sandactylus . If the vessels were "of no use" to Sandactylus, this directly undermines the evidence on which the entire conclusion is based
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