Final answer:
The visual predation hypothesis explains primate characteristics as adaptations for hunting in undergrowth and lower canopy, rather than for arboreal life alone.
Step-by-step explanation:
According to the visual predation hypothesis, primate characteristics evolved as adaptive advantages in the shrubby forest undergrowth and the lowest tiers of the forest canopy. This hypothesis, which focuses on the unique primate traits such as forward-facing eyes, grasping hands and feet, and the presence of nails instead of claws, suggests that these attributes are adaptations for hunting insects and other small prey rather than solely for living in an arboreal environment. The development of primate features helps to understand their success as predators, despite other theories like the arboreal theory, which relates primate evolution to life in trees, and the angiosperm theory that ties primate traits to the rise of flowering plants.