Do Nokia Lumia phones consume lesser battery and RAM than their Android counterparts? If so, what makes Nokia Lumia phones hardware resource conservative compared to their Android counterparts?
Microsoft has developed their OS keeping only necessary hardware usage in mind.So,they provide guidelines to developers to develop apps specifically for it.They limit an app's RAM usage to 150 MB and not unlike Android which has no such low imposed limit.
You can read below how Microsoft guides developers to build efficient apps -
App performance considerations for Windows Phone 8
Yes, Windows Phone is more efficient in terms of the amount of RAM and CPU cycles it consumes than Android. I don't know exactly why, but the fact that Android uses a Java VM as the runtime environment for apps probably accounts for at least some of that. Java is not designed for ultimate efficiency, being a semi-interpreted language with automatic garbage collection. Both of these are good features, but they do come with a certain cost in computing resources.