Writing Feedback / Students choosing subjects - writing introduction for some essay [2]

I'm writting introduction for some essay. I will send it here. Please help me check my grammar and my content. Thanks a lot

1.Topic 1:
Nowadays, not enough students choose science subjects in university in many countries.

What are the reasons for this problem? What are the effects on society?

INTRODUCTION:
Today, when students participate in university courses they do not tend to select science subject. This is a popular problem with many countries in the world. It is caused by several reason and also influence on society.