Answer:
Hormones can trigger asthma attacks.
Explanation:
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Answer:The answer is endorphins.
Explanation:Please give brainliest if right.
Although the actual questions are missing from your ask, here's how you can tell.
If the study will be messed up (added bias) through interaction with the subjects the study should be observational. For example if a biologists wanted to study the eating habits of wild birds in the tropics, they would need to do an observational study. if they did a controlled experiment, the birds will change their eating habits based on human interaction, thus making the study invalid.
If the study requires specific measurements, close monitoring, or contact and interaction with the subjects the study should be a controlled experiment. For example, if a scientist wanted to test out a new drug, the health of patients would need to be closely monitored.
Seasons, because the earths axis is tilted we have seasons. without the tilt we would never have seasons.
A species <span>a group of organisms that have similar traits and are able to produce fertile offspring.
Hope this helps! -Chat</span>