One reason it was a health threat is it caused teeth to become ground down which would then lead to infections. The same was true with their eyes and lungs, sand would be blown into their eyes or inhaled into their lungs and then could cause infections.
Answer:
C)caffeine is the independent variable
Explanation:
Caffeine is the independent variable and word recall is the dependent variable. Word recall is dependent on the presence or absence of caffeine.
Answer:
boris Johnson as he is the velocity of my grandad
Answer:
The cotton gin was a very important technological adcance in the industrial revoulution because it significantly increased the coton production.
The telegraph improved comunications and started the era of information
Explanation:
have a great day
Answer:
An observational study, not an experiment.
Explanation:
Researchers investigated reasons why different species of birds begin to sing at different times of the morning. They captured and examined birds of 57 species at different sites around England. They reported that there is a strong relationship between the diameter of a bird's eye and the time it starts singing in the morning: birds with larger eyes tend to start singing earlier.This is an example of An observational study, not an experiment.
