Yes Carbon dioxide is necessary for photosynthesis because Photosynthesis didn't go on because there was no Carbon dioxide in flask X.
The carbon dioxide was absorbed by the sodium hydroxide. In flask Y, the colour of the iodine solution turned blue black. This is because starch was present in the leaf of flask Y. Starch was present because it underwent photosynthesis.
The exchange takes place in the millions of alveoli in the lungs and the capillaries that envelop them. As shown below, inhaled oxygen moves from the alveoli to the blood in the capillaries, and carbon dioxide moves from the blood in the capillaries to the air in the alveoli.
<h3><u>Answer;</u></h3>
acceleration= 2 m/s²
<h3><u>Explanation;</u></h3>
From the second Newton's Law of motion the resultant force is directly proportional to the rate of change in momentum.
That is;
F = ma
Thus; F = 100 N, m = 50 kg
a = F/m
= 100/50
= 2 m/s²