This is parasitism because one organism (mosquito) is benefitting (by acquiring nutrition) and the other organism (human) is harmed (by the red itchy bump).
Answer: <u>Option 4; Oxygen gains electrons and hydrogen to form water.
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Respiration is a process where glucose is used and energy is released stored in this molecule. Oxygen is used during respiration as well and it gains the electrons and hydrogen to form water. And, gain of electrons is an oxidation reaction. So answer is option 4.
Since, oxygen is consumed during respiration, option 1 is incorrect.
Loss of electrons is reduction, so option 2 is also incorrect.
Glucose is used in respiration, thus option 3 is incorrect.
The answer is chromosomes. The chromosome contains the DNA nuclei. It contains all the genetic material of the parents.It is often duplicated in the cell metaphase of the cell division. Chromosomes differ from one organism to another. They are often visible under the microscope.