I think it’s a or c but I’m not good at these types of things
It is the serous membrane
Because you cannot test it or observe it.
A scientific theory are created through the scientific method, in the scientific method you need to be able observe it and experiment.
Answer:Mice can be male without Y chromosome ... Ward’s work is “a lovely example of how you can lose even a really important gene,” she says. ... don’t have Eif2s3y genes on their Y chromosomes.
Explanation: