Answer:
The cardiovascular system helps maintain homeostasis by continually supplying the central nervous system--the brain and spinal cord--with oxygen and glucose. Brain cells start dying after just one minute without oxygen. The brain is the control center for all of the body's homeostatic processes.
 
        
             
        
        
        
Explanation:
Meiosis makes genetic variety possible. It makes sperm & egg cells called gametes. Each gamete has 23 chromosomes. To make a diploid cell two gametes (sperm & cell) come together. 
During prophase 1 the chromosomes pair up with their homologous pairs so they can transfer their genetic information and exchange it between each other. It makes recombinant chromosomes that influence the genetic diversity between the same people. 
Now they are in metaphase 1, the chromosomes are in pairs in the middle of the cell. In anaphase 1, the chromosomes are pulled away by the spindle fibers. Then in telophase 1, there are two formed nuclei. Cytokinesis 1 then splits the cytoplasm. 
Now they are in meiosis 2. During prophase 2, there are chromosomes and the spindles are starting to form again without crossing over like in prophase 1. In metaphase 2, chromosomes are going to line up in the middle in both cells unlike during metaphase 1 where the chromosomes were only in pairs.  In anaphase 2, only the chromatids are being pulled away by the spindle fibers. Next in telophase 2 the nuclei reform and the 2 cells are each going to divide into 4 cells. Finally, cytokinesis completely splits the cytoplasm. 
Keeping in mind that each sex only produces one type of gamete cell (sperm or eggs), and of the independent assortment and crossing over of chromosomes, the end result will be diversity. 
 
        
             
        
        
        
1. The branches of the bronchial tree ultimately ends at the alveoli.
Bronchial tree consist of bronchi, bronchioles, and alveoli. Bronchi are formed as the lower part of the trachea divides into two tubes. Bronchioles are smaller tube divisions of the bronchi. It walls contain smooth muscle and no cartilage. Alveoli are tiny ends of the alveolar ducts, which functions as the site for gaseous exchange. 
2. Blood flows from the left atrium; mitral (bicuspid valves), the left ventricle, aortic valve, aorta, veins and heart, right side of the heart, superior and inferior vena cavae, right atrium, tricuspid valve, right ventricle, pulmonary valve, pulmonary trunk, pulmonary artery, lungs, pulmonary veins, then back to the heart...
3. Arteries and the veins differ in structures and they way they functions; Arteries carry oxygenated blood away from the heart to the body (except pulmonary artery) while veins carry deoxygenated blood back from the body to the heart (except pulmonary veins). A structural differences includes; the veins contain valves while arteries lack. Arteries have narrow lumen while veins have wide lumen. Lastly, blood carried by veins has higher pressure compared to blood carried in vessels.
4. The circulatory and respiratory systems work together to circulate blood and oxygen throughout the body. Air moves in and out of the lungs through the trachea, bronchi, and the bronchioles. Blood moves in and out of the lungs throgh the pulmonary arteries and veins that connect to the heart.
5. The cartilage rings of the trachea
They are strong but flexible tissues which support the trachea or the windpipe while still allowing it to move and flex during breathing. Additionally these cartilage rings are C-shaped to provide room for the esophagus, which lies along the back side of the trachea.
6. Functions of the larynx includes;
To protect the airway from choking on material in the throat
to regulate the flow of air into our lungs
The production of sounds used for speech 
Larynx is part of the respiratory system and is located between the pharynx and the trachea. Humans use larynx to breathe, talk and swallow. 
7. Structures that make up the pathway of air through the respiratory system starting with the external nares; We start with; External nares, nasal cavity, internal nares, nasopharynx, laryngopharynx,oropharynx, larynx, trachea, primary bronchus, secondary bronchus, tertiary bronchus, bronchiole, terminal bronchiole, respiratory bronchiole, alveolar duct, alveolar sac and alveolus.