The specific valve that prevents backflow of blood into the right ventricle when the ventricles relax is the valve.

Pulmonary valve - connects right ventricle and pulmonary trunk (which divides into right and left pulmonary arteries). It is a semilunar valve

Because the earth is not round ,but it may seem round when viewed from ,our planet but true some points earth is not round was an oblate spheroid -a square that it squashed as globe however is not even a perfect oblate spheroid.in fact isaac newton's first proposed that earth was not perfectly round but it was an oblate spheroid instead.that mean a square that is squashed as its poles and swollen at the

C) reflection (i also looked up the other choices just to make sure)