Explanation:
During implantation, the trophoblast differentiates into two distinct layers: the inner cytotrophoblast, and the outer syncytiotrophoblast.
Answer:
Testable prediction that gives direction to research.
Explanation:
A hypothesis is an explanation that can be accepted in a provisional way, but has the objective to provide sufficient guidance for further investigation.
It is also considered testable because it can be proven right or wrong, it means it is possible to be verified.
The availability of water<span />
After reading the following options, the correct one is the third option, PET scans will use tracers to inject in a vein in someone's arm. Then, the organs as well as tissues will absorb the tracer. This information makes the third option correct because PET scans mostly work with your tissues to see if there are any diseases someone may have in their body.
Hope I helped! :)
Peaculiar