The answer is C. An effector is analogous to the way a ligand (of a stimuli) binds to receptors on the surface of the body and triggers an impulse in the neuron. An effector, on the other hand, occurs internally of the body and when the effector molecule binds to the receptors of the organ that it stimulates or suppresses, a cascade signaling pathway in the cells occurs and the cells/organs responds requisitely.
Remain stable is the answer
The right answer to this question is option D. Carotenoids are categorized into two major divisions: carotenes and beta carotenes
First, let's check option A, it says that the carotenoids include red, orange and yellow pigments, that's true, we can check that on lab for example, a vegetable that can be mentioned here are carrots, it has lots of this and it's very healthy too, and remember, there isn't a single animal that can produce carotenoids, so they need to grab it from nature.
The second option, B. says that sometimes carotenoids are sometimes called as acessory pigments, that's true too, some studies consider them acessory pigments, so, they're not alone there, there are different kinds of pigments that can be on that plant, and they're also very important for the animals. Option C refers to beta carotene as the most abundant carotene in plants, that's true too, we can also find other kinds of carotenoids on plants, but this one as it's seen in lab, is the most common one. The last one, D, isn't true, the two major divisions are: Xanthophylls and Carotenoids, beta carotenoids are a type of carotenoids, not a different group.