What is the path that blood takes through the blood vessels and back to the heart?

Some tools have graduations to show multiple measurements. for example, a ruler may have graduations for both millimeters and centimeters. when measuring the length of an earthworm, which graduations would allow for the most accurate measurement? millimeters centimeters decimeters meters

If t=tall and t=short what will be the physical appearance of the offspring the cross below? a. some will be tall and some will be short b. they will all be tall c. they will all be short d. they will be medium height

Why are current extinctions of concern to enviromentalists?