Answer:
A Carbon Dioxide ( CO2)
Explanation:
During the process of photosynthesis, cells use carbon dioxide and energy from the Sun to make sugar molecules and oxygen. ... Then, via respiration processes, cells use oxygen and glucose to synthesize energy-rich carrier molecules, such as ATP, and carbon dioxide is produced as a waste product.
The answer to your question would be B
One problem with this hypothesis is that the student didn't write about why this hypothesis might work - what is the underlying mechanism. The thing is that one might want to write the underlying mechanism or explanation in his hypothesis. Another problem with this hypothesis is that it's very hard to measure and be sure that following exposure to white chocolate, people are happier and that it's not a consequence of something else.
Answer:
constant = changes and control is used as the basis of comparison
Explanation:
Constant variables are variables that do not change
e.g such as the temperature ( if it's meant to be kept at a constant temp).
Control variables are meant to be kept constant to allow for a comparison and thus determine the effect of IV (independant variable) and DV ( dependant variable)