Making a semi transparent image

[marism77777708]

Hello everyone I am planning to do an image for a medical journal, and I have found kind of what I want to. I am kind of new in illustrator, but if you could give me directions to a tutorial to do something like the image I've attached, I'll be grateful

[Monika Gause]

Could be achieved by using gradient meshes. In the mesh you can make some colors with reduced opacity.

[Mike_Gondek · Accepted solution]

First make a group of you liver,

and change the opacity at the group level. Sorry my example is not the best

or blending mode