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.
Which of these help in the asexual reproduction of black bread mold?
To answer this you need to know which phylum the mould belongs to. If you search it you find it belongs to Zygomycota, therefore it produces zygospores.
1.underground stem -- for storage of food ex. potato , ginger.
2.spines for protection ex. citrus , bougainvillea
Answer:
Shutting down factories that discharge materials to the rivers.
The largest sum of US pollution currently caused by factory-related substance
Explanation:
my pfp!
Answer:
#1 false its difficult but also possible. #2 true and #3 False. the Salivary gland in the mouth make 1.5 liters a day
