Answer: Possession of Valves
Explanation: Veins possess valves which ensures that blood flows in only one direction. Valves helps blood to flow back to the heart against gravitational force.
Arteries don't have valves because the pressure originating from the heart is capable of causing the blood to flow in one direction.
 
        
             
        
        
        
Answer:
b. False
Explanation:
All living organisms such as plants and animals require energy to function properly (life activities). Thus, the organelle where energy from nutrients is released is generally referred to as mitochondria. Animals retrieve energy using mitochondria to do cellular respiration because they typically act like a digestive system by taking in nutrients, breaking them down and obtaining energy rich molecules for cell-life activities.
Cellular respiration can be defined as a series of metabolic reactions that typically occur in cells so as to produce energy in the form of adenosine triphosphate (ATP). During cellular respiration, high energy intermediates are created that can then be oxidized to make adenosine triphosphate (ATP). These intermediary products are produced at the glycolysis and citric acid cycle stage.
Basically, mitochondria is one of the cell organelles found in all living organisms and it is known as the powerhouse. Therefore, mitochondria provides all the energy required in the cell by transforming energy forms through series of chemical reactions; breaking down of glucose into Adenosine Triphosphate (ATP) used for providing energy for cellular activities in the body of living organisms.
Hence, during respiration, most ATP is formed as a direct result of the net movement of protons down a concentration gradient but not potassium against a concentration gradient potassium.
 
        
             
        
        
        
They are inversely related. As the distance increases the magnetic attraction decreases and when the distance decreases the magnetic attraction increases
        
             
        
        
        
Answer:
basically "building blocks"
Explanation:
Living things are made up of very large molecules. These large molecules are called macromolecules because “macro” means large; they are made by smaller molecules bonding together. Our body gets these smaller molecules, the "building blocks" or monomers, of organic molecules from the food we eat.