Final answer:
Primates, including humans and tarsiers, cannot synthesize Vitamin C internally and must obtain it from their diet, unlike most other animals and plants.
Step-by-step explanation:
True, primates are unable to manufacture Vitamin C and therefore must consume it daily. In contrast to plants and most animals, such as cows, which can synthesize Vitamin C internally, primates like humans and other species including tarsiers require external sources of this vitamin in their diet. Essential nutrients like vitamins are often lost metabolic abilities through evolutionary time since these vitamins are usually found in the diet of heterotrophs. Therefore, to prevent deficiencies, primates must obtain their required vitamins, especially Vitamin C, from their dietary intake of fruits and vegetables.