The answer is d because natural selection is the process in which organisms adapt to their environment and all of these answers fall into examples of natural selection
Inferior mesenteric artery
The part of the colon located distal to the left colic flexure is derived from the hindgut is supplied by the inferior mesenteric artery. The distal part (lower third of the rectum) is supplied by the internal iliac artery. The ileocolic artery supplying the cecum is a branch of the superior mesenteric artery.
1.Discomfort in the salivary glands (in the front of the neck) or the parotid glands (immediately in front of the ears). Either of these glands may become swollen and tender.
2.Difficulty chewing.
3.Pain and tenderness of the testicles.
4.Fever.
5.Headache.
6.Muscle aches.
7.Tiredness.
8.Loss of appetite
A substance called bile neutralises the acid to provide the alkaline conditions needed in the small intestine.
so your answer is Bile !!
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