Hi, I posted this under General Physics but I thought I should post this under the math section too in case there are mathematicians who do not read posts under General Physics. I read some papers online about Calabi-Yau surfaces but I have some basic questions about them if you can answer them for me. 1. Who proved that Calabi-Yau mfds fit into string theory? Why does C-Y surface fit into string theory, instead of any other surfaces? 2. I googled C-Y surfaces and saw many beautiful pictures of them. But why do they look like that? Do you have explanation other than the fact that they have a trivial canonical bundle? 3. What are different kinds of singularity types that can occur on a C-Y surface (just an intuition of them will be fine)? Why is the orbifold singularity considered to be the simplest singularity on a C-Y surface? 4. Why do singularities form on C-Y surfaces and what physical meaning do they have? 5. Why should we resolute singularities? 6. An orbifold is locally C^n/G where G is a finite subgroup of SL(n,C) and C = complex numbers. So where are the singularities? How do you see that? 7. What is a physics meaning (the physical perspective) of a canonical bundle? 8. How much of algebraic geometry do mathematicians and physicists use to study Calabi-Yau manifolds and string theory? I'm sure they do use PDE/ODE and differential geometry, correct? Thank you in advance for your time!