What is the major function of the valves found in human veins?

What is pangea and what is a himalaya mountain

If China has a population of 1,355,935,022 people and an area of 3,705,405 mi^2 what is the population density of China? a. 77 people/mi^2 b. 123 people/mi^2 c. 0.00273 people/mi^2 d. 366 people/mi^2

Thr light-independent reactions of photosynthesis are also known as the a. Calvin cycle b. priestly cycle c. Benson cycle d. van Helmont cycle

Which represents a negative impact of technology? O A. Increased recycling O B. Renewable energy sources O C. Higher food production O D. Climate change

A variable that is manipulated within an experiment is known as the

What element is found in all organic compounds? oxygen nitrogen carbon helium

Prior to the time of charles darwin, it was widely believed that all organisms appeared on earth at the same time and remained unchanged throughout history. which of these proved to be the biggest influence in the development of this idea? a.

The adult spinal cord ends between the level l1 and l2 of the vertebral column. True or False

Which part of the eye directs nerve impulses to the brain? lens cornea pupil retina

Which of the following could NOT be the formula for a carbohydrate? C6H12O6 C8H16O8 C10H20O10 C11H11O22