Hi,

According to DU admission eligibility criteria for B.Sc Zoology or microbiology course the eligibility is as follow -

• 55% or more marks in the aggregate of Physics, Chemistry, Biology/Biotechnology/Biochemistry (Practical & Theory together) and 50% or moremarks in one compulsory language i.e. English.
• Merit will be calculated based on aggregate percentage in Physics, Chemistry,Biology/Biotechnology/Biochemistry.

So from the above eligibility criteria a for admission to bsc Zoology or microbiology a candidate should have following subjects combination -

• Physics
• Chemistry
• Biology/Biotechnology/biochemistry
• English.

So you can not include economics for calculating best four percentage.

Hope it helps.