How does the object distance (do) of a convex lens compare with the object distance of a concave lens? A. Both are negative. B. Both are positive. C. The object distance of the convex lens is negative, and that of the concave lens is positive. D. The object distance of the convex lens is positive, and that of the concave lens is negative.

dopamine..

"it was found that some people who were taking the drug l-dopa to raise their levels of dopamine were developing schizophrenic-like symptoms supporting research a strength of the dopamine hypothesis is that there are many studies which have shown support for the neurochemical explanation."

t = 1/400 h   ⇔ 0.0025 h ⇔ 9s ⇔ 0.15 m

any of the answers are correct.