I always find it confusing when the Bible says that God created Adam and Eve and that all mankind are their offspring. The Quran also says the same. If it was so how did the different races come to be. Lets assume that Adam and Eve were both white, how did the black man and the china man and the indian enter the world. Let us also assume that they are of different races, say white and black, I know the best they can give birth to is a mulato (half caste). Someone please educate me on this.

First and foremost let’s be clear about the fact that religious beliefs and worldviews are unfalsifiable propositions. These are, therefore, irrationally held beliefs. The narratives contained in the Holy Scriptures of the three Abrahamic religions (Judaism, Christianity and Islam) and in similar scriptures identified with other world religions derive from ancient myths and folklores. If you believe them, you are on the same pedestal as those who believe in the ancient Yoruba myth/folklore which maintains that when the Orisas were coming to this earth, Olodumare gave Ogun, the deity, a machete/cutlass to make a footpath linking heaven and this planet earth and enabling other Orisas to make their respective journeys, by foot, from heaven to the earth. Guys, this as well as other scriptural narratives arguably aren't true.

Now to your question. You sincerely need to get yourself a copy of Darwin’s ‘On the Origins of the Species’, give it a good read, paying due attention to, amongst other things, his discussion of: (i) the causes of variability, especially variation under domestication and nature; (ii) sexual selection and how species change through the process of natural selection and dispersal; and, (iii) hybridism. Good luck!