Name three challenges for scientist today

Select the situation bellow that would produce a total displacement of zero. a. a trip to the moon and then to mars b. a horse galloping from one end of a field to another c. the criss-crossing path of a bug as it flies from flower to flower d.a round-trip ride to school and back

Vessels draining the myocardium of the heart, open primarily ,into which chamber?

What factors contribute to the effect an environmental toxin has on the human body?