Three color receptors that responded in an opponent-process fashion had been proposed by ; this arrangement was later verified by in monkeys.

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Three color receptors that responded in an opponent-process fashion had been proposed by Hurvich and Jameson; this arrangement was later verified by DeValois in monkeys.

Explanation:

In "An opponent-process theory of color vision" (1957), Hurvich and Jameson developed the opponent-color system. In "Color Vision Mechanisms in the Monkey" (1960), De Valois confirmed the existence in monkeys of color-opponent ganglion cells in the retina and color-opponent cells in the lateral geniculate nucleus of the thalamus. De Valois himself states in his research that there´s a clear close parallel between the behavior of what he calls "on-or-off cells" and the findings o Hurvich and Jameson.

organisms that lack symmetry are called asymmetrical and belong to phylum porifera/sponges.

organisms with specialized stinging cells belong to phylum cnidaria. stinging cells are called cnidoblast cells.

cnidarians show two morphological forms : polyp (sessile) and medusa (mobile)

filter feeding is observed in porifera members.  

alternation of generation is observed in coelenterata or cnidaria. there is alternation of asexual polyp form and sexual medusoid form. it is also referred as metagenesis.

oak trees? ? what was listed