Natural selection would not take place without what?

Which of the following represents an upside-down image? o a. +doo b. -doo c. +mo d.-m

Find an expression for the electric field e⃗ at the center of the semicircle. hint: a small piece of arc length δs spans a small angle δθ=δs /r, where r is the radius. express your answer in terms of the variables q, l, unit vectors i^, j^, and appropriate constants.

Asign is hung between two cables as illustrated below. if the sign weighs 350 n, what is the tension (in n) in each cable?