Answer:
A) Receiving a vaccination.
Explanation:
 
        
             
        
        
        
There are different types of observers. Casual observers differ from scientific observer. Seeing and observing are two different things. Not that everybody seeing is actually observing the thing. 
A casual observer just sits back and watch for something to happen while a scientific observer comes up with some hypothesis to work on it.  
        
                    
             
        
        
        
Answer:
The <u>PCO₂</u> -carbon dioxide partial pressure- in the alveoli is 40 mm Hg and that of the blood entering the pulmonary capillaries is <u>45 mmHg</u>. This causes <u>carbon dioxide</u> to diffuse down its partial pressure gradient from the blood into the alveoli.
Explanation:
Gas exchange is a physiological process that involves the entry of oxygen into the body and tissues and the exit of carbon dioxide, a product of metabolic reactions.
At the pulmonary level, gas exchange occurs between the alveoli and the alveolar capillary, and the diffusion of gases across the alveolar-capillary barrier is dependent on a pressure gradient due to the partial pressure of gases.
In the case of CO₂ the diffusion goes from where the partial pressure is higher to where it is lower, i.e. <u>from the alveolar capillary, where the PCO₂ is 45 mmHg, to the pulmonary alveolus, where the PCO₂ is 40 mmHg</u>.
Learn more:
Gas exchange brainly.com/question/4469204
 
        
             
        
        
        
Answer:
see in explaination
Explanation:
Density (D) is a quantity defined as mass (m) per unit volume (v): D = m ÷ v. Since these three quantities are related, you can find one of them if you know the other two. This is more helpful than it sounds because density is often a known quantity that you can look up, assuming you know the composition of the material.
Calculations are straightforward for solid objects, but things get more complicated for liquids, where density changes with temperature, and for gases, for which density is dependent on temperature and pressure.