Colour jpeg

A jpeg will come into Illustrator as a flattened file. It's individual components cannot be selected individually and recolored in Illustrator. If you want to recolor the segments you can open it in Photoshop and use the Magic Wand tool to select each segment one at a time and fill it with the desired color. Then you can bring the finished jpeg into Illustrator keeping in mind that it is a raster object and is affected by resolution. That means if you enlarge it at all it will start to become pixelated. A shape like the one you're showing would be better off being redrawn as a vector object in Illustrator.