Can a science student become CA

You should start learning basic concepts of accounts

If you really believe in hard work and determination then believe me it's not difficult to even do CA after being a science or a non-science student. Anything will be possible if you are motivated enough to do it

Starting and finishing CA would not be difficult for a kid who has studied science in school or college. The main reason for this is that the CA curriculum is separated into three stages: CPT, IPC, and Final are the three levels of certification. Students are tested on the fundamentals of accounting, math, economics, and law during the CPT stage.

Assuming the basics of a science student is always strong, it will not be difficult to cope with the CA Course

Here are some alternatives to CA course in today's globlised era :
1. Get an international degree in accounting / auditing e.g.  ACCA, ICAEW, CIMA, CPA (USA / AUS / NZ), CMA (USA), CIA, CISA, CFE etc. (all these courses are much easier than CA curriculum and several online / offline coaching classes are available in India).  
2. Go for a course in ERP - SAP, Oracle EBS, Microsoft Business Central (MS Dynamics).  
3. Go for a course on Data Analytics tools (ACL, IDEA), Data Visualisation / Business Intelligence Tools (R, Power BI, Tableau, Quilkview etc.).  
4. Go for a course on a Robotic Process Automation (RPA) tool (e.g. UiPath, Automation Anywhere, Blue Prism etc.).  
5. Go for a course on a GRC suite (e.g. RSA Archer, ServiceNow, SAP GRC etc. ) 

After gaining these degrees / certifications / skill sets, you will easily get an opportunity in an IT company, Big4, MNC, KPO, Global Delivery Centre / Shared Services Centre of an MNC / Big4.