Answer:
Superior vena cava
Explanation:
Of the two vena cava, the superior vena cava is the large vein without valves that is responsible for conveying de-oxygenated blood from the upper extremities and body (neck, chest, arm and head) above the diaphragm to the right artrium.
Although the superior vena cava is a large vein, it also short; it is about 2 cm wide and 7 cm long. 
When there is an obstruction of the superior vena cava, it can result to the enlargement of the veins and could lead to chest pain and breathlessness.
 
        
             
        
        
        
Answer:
In developmental biology, embryology would be the early cellular stages of development. 
Explanation:
 
        
             
        
        
        
Answer:
Pesticides vary in their effects on bees. Contact pesticides are usually sprayed on plants and can kill bees when they crawl over sprayed surfaces of plants or other areas around it. ... When a bee comes in contact with pesticides while foraging, the bee may die immediately without returning to the hive.
 
        
             
        
        
        
<span>When practicing birth control as natural family planning, it is not true that it is almost 100 percent effective. Birth control as natural family planning does require careful tracking of the menstrual cycle, demands focus on bodily changes, and does require women from having sex on days ovulating and following. Even if sex is is had outside ovulating days, it is possible to get pregnant, thus it is not 100 percent effective.</span>