“make due allowance”应该怎样理解?

题目

“make due allowance”应该怎样理解?
这句话里面的No one ought to feel surprise at much remaining as yet unexplained in regard to the origin of species and varieties,if he makes due allowance for our profound ignorance in regard to the mutual relations of all the beings which live around usx09求大神帮助

答案

to excuse,taking mitigating factors into consideration