Answer:
Option D, A subject is observed both before and after two exposures to the treatment.
Explanation:
In A-B-A-B design the alphabets have following meaning
a) First A – It is the baseline value or the value measured before treatment
b) First B – It is the treatment measurement
c) Second A - It is the withdrawal of treatment
d) Second B – It is the reintroduction of treatment
The second A is known as the reversal phase in which the intervention is withdrawn to see if the target behavior returns to the baseline behaviour
Thus , there are two measurements involved one before the intervention and second after the intervention
Option D is correct
Niches, trophic levels, and ecological processes of a biological community.
Answer:
low, under, beneath, down, or below normal
Inherited genetic factors : hope it helps
Answer:
c
Explanation:
mRNA is basically the same except it has U instead of T
