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The second A is known as the reversal phase in which the intervention is withdrawn to see if the target behavior returns to the baseline behaviour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
<u>Cell culture i</u>s the method applied by scientists to grown, cells in the laboratory setting to study the cells for particular reasons.
Explanation:
Cell culture is basically a method for survival, reproduction etc which are done under controlled conditions in the space outside the environment. This is also used for data mining.
Purpose: Cell culture is used for propagation of virus
Advantages:
- Vaccine production by replication of virus
- Detection of viral cell of virus
- Convenient easy and economical method
Disadvantages
- Maintenance of sterile aseptic conditions.
- Increases microbial contamination
- Cross contamination takes place
The answer is D because <span>In </span>exocytosis<span>, materials are </span>exported<span> out of the cell via secretory vesicles. In this process, the Golgi complex packages macromolecules into transport vesicles that travel to and fuse with the plasma membrane. This fusion causes the vesicle to spill its contents out of the cell. Exocytosis is important in expulsion of waste materials out of the cell and in the secretion of cellular products such as digestive enzymes or hormones.</span>
I don’t know maybe 29 or I have no clue