Contact transmission<span> is the most common form of </span>transmitting<span> diseases and virus. There are two types of contact </span>transmission<span>: </span>direct<span> and </span>indirect<span>. </span>Direct<span> contact</span>transmission<span> occurs when there is physical contact between an infected person and a susceptible person. Cheers and god bless
AlexFray555
Please put brainliest!</span>
For Iron:

For Oxygen:

These are the two chemical symbols for the two elements found in Iron Oxide.
<span>The correct answer is( A) blood.
when the buffer solution its PH value changes very little when a small amount
of strong acid or base is added to it, and here the bicarbonate buffering system is used to regular the PH of the blood that keeping the PH at nearly constant value by maintaining the original acidity or basicity of the solution.</span>
Answer:
1) Salts X and Y
2) The solubility of the salts
3) a) The solvent
b) The solvent temperature
Explanation:
1) The independent variable is the variable that is suspected to be the cause of the subject of the investigation
The given investigation is meant to investigate the solubility of different salts
Therefore, the solubility is expected to be dependent on the type of salt, and the independent variable is the type of salt, X or Y
2) The dependent variable is the effect meant to be observed in the investigation, which is the solubility of the salt in water at room temperature
3) The control variables are the variables which are held constant during the investigation, including;
a) The solvent used if the investigation; water
b) The temperature of the solvent; Room temperature