Hi the adjective here isn’t directly attributed to the noun.
Tha an fhuil dearg. - the blood is red
An fhuil dhearg - the red blood
No, a general description would be “tha fuil dearg.”
If fuil is feminine, shouldn't it cause lenition? Or is it an exception?
I wouldn´t use the definite article here as the sentence describes blood in general, or doesn´t it?
No that would be "tha fuil dearg".
Should it not also accept "The red blood"?
No, not here as there is a verb involved - tha. :)