单选题One problem of using pig organs on humans is ______.A the size of the pig organs.B the quick rejection of the transplant by human bodies.C the speed of their maturity.D the technical complexity of the operational process.
题目
单选题
One problem of using pig organs on humans is ______.
A
the size of the pig organs.
B
the quick rejection of the transplant by human bodies.
C
the speed of their maturity.
D
the technical complexity of the operational process.