What is the complete back-and-forth motion of an object called?

In a simplified model of the human eye, the aqueous and vitreous humors and the lens all have a refractive index of 1.40, and all the refraction occurs at the cornea, whose vertex is 2.60 cm from the retina. what should be the radius of curvature of the cornea such that the image of an object 40.0 cm from the cornea’s vertex is focused on the retina?

You've already seen the value of 9.8 in this lesson. what's this value called? what quantity does it represent?

Explain what will happen if decomposers were apsent from a forest ecoysystem.