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.
Answer: Antenna
Explanation:
The morphogenesis is a process by which the egg get transformed into a matured adult insect. The egg transform into several transitional stages such as embryo, larva, pupa and finally to adult insect.
The fruit flies undergoes three development stages during morphogenesis these includes the egg, larvae and pupa. The fruit flies can develop into adult within 1-2 weeks at room temperature. The egg as well as larval stages takes a span of eight days whereas the pupal stage takes six days for development.
The embryo enclosed inside the egg exhibit three important parts the head, thorax and abdomen the antenna is the structure which develop in adult flies.
Answer:
By donating your organs and tissue after you die, you can save or improve as many as 75 lives. As many people are waiting for transplants
Explanation:
helping/improving lives is good
The discovery of the cell was possible do to the invention of the Microscope.
Answer: D. They must eat in order to gain nutrition
Explanation:
