Triangles became visible
First of all , hello to everyone , i just joined your from , and so far have learnt so many things 
Anyways . Here is my problem .
I'm not an expert in 3d modelling , it's been 3-4 weeks since i first started modelling , and this m16 is my final project that i'm working on . But today i have encountered an interesting problem . All the triangles became visible ! So it's really hard to work on it for me atm , and this problem has affected all my saves , so every save of this project became almost no-way to work on . Here is a picture of it :
How can i solve this problem ?
Anyways . Here is my problem .I'm not an expert in 3d modelling , it's been 3-4 weeks since i first started modelling , and this m16 is my final project that i'm working on . But today i have encountered an interesting problem . All the triangles became visible ! So it's really hard to work on it for me atm , and this problem has affected all my saves , so every save of this project became almost no-way to work on . Here is a picture of it :
How can i solve this problem ?