What is this tissue in chicken called? I previously asked a question on whether chicken contains suet and the answers was no. however if you look at his picure the tissue highlighted in red looks like suet. If not suet, what is this and how is it different from suet?

Also what parts of a chicken contain these the most?
"Suet" is beef fat, especially from around the cow's kidneys. By definition, a chicken cannot contain suet, unless it's recently eaten some beef.

The bits you've circled are fat deposits, though, like suet. In a butchered chicken, it's easiest to find similar fatty deposits on the thighs, back, and tail. The breast and wings have comparatively little.