color layers is simply color layers
Using blend modes. Blend modes U can access from top of LAYERS palette for example
RGB, CMYK, Grayscale, Lab, Indexed color are color modes in Photoshop. What you want to ask? Why we use color modes? To manage colors in image based on image purpose.
There are many resources and websites that offer information about Photoshop layers. Some of these websites that offer information are Adobe, Photoshop Essentials and Photoshop Cafe.
Photoshop training can be acquired from various ways, one of them is the Adobe Photoshop Basics Online Course. There are various lessons on Navigating the Workspace, Working with Documents, Image Modes & Color Selection, Selections and Masks etc. It is also available free of cost.
Open the Layers window.
Yes, .psd files maintain the layers you create in Photoshop so that the next time you open your .psd file in Photoshop you can continue to work directly onto the layers.
What is colour channel in photoshop?
One layer.
To store image parts.
To select all layers in photoshop for a PC open up your layers window (It is under window - layers), hold down the shift key and click on each layer that you want to group together or edit.
Flattening layers just merges all layers down into one. It reduces file size, but once the image is saved and Photoshop is closed, you will no longer be able to undo the change and edit those layers separately.