Compounds consist of atoms of different elements. In compound the atoms are present in fixed proportion. By changing the proportion compound will changed. For example,
Nitrogen and oxygen reacted to form the compound. By changing the proportion both will form different compound.
NO₂
Nitrogen dioxide consist of one atom of nitrogen and two atoms of oxygen. Their ration is 1 :2
NO
In nitric oxide one atom of oxygen and one atom of nitrogen are present.
Their ratio is 1 : 1.
N₂O
Nitrous oxide consist of two nitrogen atoms and one oxygen. Their ratio is
2 : 1
N₂O₄
Dinitrogen tetroxide consist of two nitrogen atoms and four oxygen atoms. Their ratio will written as 2 : 4
N₂O₅
Dinitrogen pentoxide consist of two nitrogen atoms and five oxygen atoms. Their ratio will written as 2 : 5
<h3>Global travel and spread of certain species</h3>
Explanation:
Many pathogenic species of bacteria, virus, and other microbes are more prevalent in developing or tropical countries rather than in developed countries.
When an individual’s immune system is weak they become more susceptible to get infected and become carriers of that particular species.
The species grows, develops, and multiplies in the host’s body and when the traveler travels to his/her home country or any other place he/she can transmit the disease to others and again the species grows in numbers. Higher the rate of spread of infection higher is the increase in species.
C. <span>eukaryotic cells contain organelles that are enclosed in membranes.</span>
Oxygen enters the blood in the A. Bronchi.
