Answer:
Exoskeletons provide less mechanical leverage.
Explanation:
There are two types of skeleton in living beings: the endoskeleton (which vertebrates possess, is lined with epithelial tissue and has bones and cartilage) and the exoskeleton, a skeletal structure that is located outside the body of the living being. , is an external skeleton. They are common in invertebrate animals, which have no internal bone structure.
The exoskeleton is a tough but flexible outer layer, not formed by bones, unlike the vertebrate endoskeleton. Its function is mechanical, chemical and biological protection, avoid excessive water loss, muscle support and serves as a connecting point for legs, wings and other appendages. However, this type of skeleton provides less mechanical leverage.
On the other hand, the endoskeleton is the name given to the internal skeleton, which is inside the body. This body structure is mainly seen in vertebrate animals and has the function of supporting and moving the body, as well as protecting some internal organs. Unlike exoskeleton, the endoskeleton provides more mechanical leverage.
 
        
             
        
        
        
Answer:
The Mitral/Bicuspid Valve
Explanation:
The heart is composed of 4 chambers: left and right atria, and left and right ventricles. The “right heart” (right atrium and ventricle) receives deoxygenated blood from the systemic circulation through the Vena Cava, and impels this blood towards the lungs through the Pulmonary Arteries where it will be oxygenated. The “left heart” (left atrium and left ventricle) receives oxygenated blood from the pulmonary circulation through the Pulmonary veins and impels this blood towards the systemic circulation through the Aorta artery.
The systemic and pulmonary circuits work in series, and maintaining the unidirectional course of the blood flow is very important. This can be done by the presence of fibrous valves that are present between the atrium and the ventricles, and in between the ventricles and the Pulmonary/Aorta artery.
The location of these structures are as follows:
Systemic circulation ⇒ Right Atrium → [Tricuspid Valve] → Right Ventricle → [Pulmonary Valve] → Pulmonary Artery ⇒ Pulmonary circulation
Pulmonary circulation ⇒ Left Atrium → [Mitral/Bicuspid Valve] → Left Ventricle → [Aortic Valve] → Aorta ⇒ Systemic circulation 
 
        
             
        
        
        
ANSWER
D. a star hope this helps :)
        
             
        
        
        
The answer is C because plants and animals need nutrients to life