How are CPU architecture and word size related?
It's simple - 32 bit word size, or 32 bit architecture, mean exactly what the person using the expression means. No more, no less. You can't draw any conclusions from it. 

For example, there's an Intel 32 bit architecture that can address 64 GB of physical RAM, and no Intel 64 bit architecture that can address anything near 2^64 bytes of physical or virtual memory, while 32 bit PowerPC supported 2^53 bytes of virtual memory. 

64 bit POWER has 32 bit instructions. 32 bit Intel has instructions from 8 bit to over 100 bit. 

32 bit ARM is what it is, and 64 bit ARM is what it is. Some with 32 and 64 bit x86, except they are different. And so on. Don't make any assumptions, they will all be somewhere between wrong and not quite right. 

If you want to pass an exam, learn the answers that the exam expects (sad but true).