Science

Yes, you can choose Maths with B.Com.

No, now there is no possibility except management quota seats. And, for management quota seats, you have to visit college and ask college officials authorities.

Yes maths marks are mandatory for BA Hons in economics in DU.

Yes,basic.Breadth-first search (BFS)is an important graph search algorithm that is used to solve many problems including finding the shortest path in a graph and solving puzzle games (such as Rubik's Cubes). Many problems in computer science can be thought of in terms of graphs. For example, analyzing networks, mapping routes, and scheduling aregraph problems. Graph search algorithms like breadth-first search are useful for analyzing and solving graph problems.

Biotech deals with the technical components used in the field of medical. You got the knowledge and get opportunity to work with these equipment. There is lot of opportunity in this field. But, in Indian market share for Biotech is little bit low.

If you not want to pursue Courses which is offered through JEE and NEET are as follows:
B.Sc in various streams. HM
NDA preparation
Mass Communication and many more.

No, there is no any college under UPTU, which can offer you B.Sc. You have to crack other entrance test and those entrance depends on the basis of colleges and university.

Hello Reshma,
GATE is an entrance exam for admission for MTech or ME courses in many institutions in India. But, it's not for MSc.