Part Refresh the simulation, and then add six protons and six electrons to make a neutral carbon atom. Click the plus sign on
the Mass Number window. What's the mass number of this carbon atom?

object 2 because all the other ones are wrong

answer: the correct answer for the fill in the blank is rods.

rods are the specialized photoreceptor cells that are present in the retina of human eye. they are responsible for vision in the night time ( also called scotopic vision). they have very low visual acuity and color distinguishing ability.

as they are responsible for vision in night time, therefore they are found predominantly in the nocturnal animals.