If the mother of a child is blood type a positive and the child is ab negative then what blood type is the father?

Which experiment would most likely contain experimental bias ?

How is the national wildlife refuge system similar to the pacific region coastal program? a. both programs are concerned with providing habitats for wildlife b. both programs are primarily concerned with preserving fish species c. both programs have set aside 150 million acres of land d. both programs are under the u.s. fish and wildlife service

How can you tell the difference between rough er from smooth er?