Why is the water cycle so critical to all ecosystems
A. Water provides energy to producers
B. Water is the base of all food chains
C. All living things need water in order to survive

Sammi is studying the interaction of the digestive and circulatory systems in the human body. she has listed various processes that occur in each of the systems. put the processes in order to describe the interaction between these two systems. tiles nutrients diffuse through the villi of the small intestine. digestive processes break nutrients down in the mouth, stomach, and small intestine. blood is pumped through the circulatory system to deliver nutrients to other organs. nutrients are ingested at the mouth. nutrients enter the capillaries of the circulatory system. sequence

Which of these serves as a reference for comparison during a scientific investigation? a)outcome variable (dependent variable) b) test variable (independent variable) c)control group d)hypothesis

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