Answer:
C-None of these are found in an observational study
Explanation:
(A.) controlled variables are a part of what's found in a controlled experiment. (B.) manipulated variables are a part of what's found in a controlled experiment. (C.) Answer choice A. or Controlled variables, Answer choice B. or Manipulated variables, and Answer choice D. or Control groups are a part of what's found in a controlled experiment. (D.) Control groups are a part of what's found in a controlled experiment. Therefor this only leaves one answer and that answer is Like I said C-None of these are found in an observational study.
False the embryo is implanted into the animal that donated the egg
No Predetors will go for any easy prey young sick injured old ect.
19 chromosomes is prolly right.