Are RAM and storage physically located on smartphone's SoC or not? I started to learn about Android-based devices' hardware and already have learned about SoC, which includes CPU, GPU, connectivity modules, etc in one chip. I have found an example of SoC structure (Snapdragon 600):



Some sources say that SoC also includes RAM and storage, while others say that RAM and storage are placed on other chips which are separately soldered to the motherboard.

Which answer is correct? I'm sorry if this is a stupid question, I'm a newbie. Also, maybe you have some helpful articles to read. Thank you!
Both answers are correct. 

A SoC can contain RAM and flash but it does not have to. What variant is used is chosen by it's manufacturer and therefore every device type can have a different SoC and motherboard layout. And as there are dozens of manufacturers and hundred of different Android devices sold you will find any combination of on SoC with or without integrated RAM and flash.

If you are interested in a specific device check the device tear down section from iFixit for example. They usually mark the different chips on the motherboard so that you can identify which chips are separate chips (e.g. flash memory and/or RAM).

Some times even devices that share the same name like Samsung Galaxy S10 contain different SoC and motherboards. In this case the devices for the markets USA, Canada, China and Japan have contain a Qualcomm Snapdragon instead of a Samsung Exynos SoC.