What are the elements of a nebula consist of

What is the answer for this. the correct answer only

Use the right-hand rule for magnetic force to determine the charge on the moving particle. this is a charge.

If the radius of curvature of the cornea is 0.75 cm when the eye is focusing on an object 36.0 cm from the cornea vertex and the indexes of refraction are as described before, what is the distance from the cornea vertex to the retina? express your answer to two significant