Hi

After much consideration I conclude the following (not entirely convinced but here goes!)

4  Weight gain is an increase, an overall increase in tissue volume so a tissue change.  Without additional symptom information it could be water retention indicating old brain - brain stem:  tissue change, adenoma, stress phase on the symptom compass.

5  Underactive thyroid is a functional change reduction leading to not moving about as much, less energy, feeling cold and weight gain. These symptoms correspond with old brain - brain stem:  functional change - reduction after very long stress phase, temperature - sensation of inner coldness, tissue change - adenoma in the stress phase section of the compass.

I was drawn by other sections but since the task video indicated the thyroid - brain stem connection, I had to stick with that.