4 is nucleus because it’s in the middle
The aveolus is surrounded by capillaries. So capillaries carry deoxygenated blood to the alveolus where the oxygen from the alveolus diffuses into the blood in the capillaries. The deoxygenated blood is now oxygenated and is carried out of the lung via capillaries that then merge into the pulmonary vein.
In other words, alveolus does not have oxygenated blood it just puts oxygen into the deoxygenated blood hat this brought in.
Answer:
hand lens is used to make small object to appear larger hence visibility is easily attained
An allele is a variant form of a gene. some genes have a variety of different forms,which are located at the same position, or genetic locus, on a chromosome.
Answer:
Tropical Zone
Explanation: Its near the equator with warm air masses with the average temperature in the coldest month is 18 °C. This is warmer than the average temperature of the warmest month in the polar zone.
