Answer:
12
Explanation:
Suppose the four different strains are P, Q, R, S. Thus, the first infection can be from any of the four strains and it occurs in 4 ways.
Since an individual cannot be infected again with the strain from which he/she is been previously infected;
Then, at the second time;
The possible number of strain to be infected with = 4-1 = 3 ways
Thus; the number of possible different levels of severity can be viewed by forming two lettered word P, Q, R, and S without repetition which is:
= 4 × 3
= 12
Answer:
a. establishment of left-right asymmetry
Explanation:
- Cardiac looping is the process in which the heart transforms itself from a straight embryonic heart into a loop that is wounded helically.
- The looping of the heart takes place on the 23rd day of development.
- As a result of this looping, there is bending of the cranial portion of the heart to the towards the right end and the caudal portion of the heart towards the left end.
- At the end of this looping the atrium takes up a dorsal and cranial position and the ventricle is displaced towards left.
- Thus, the outcome of looping is the establishment of left-right asymmetry.
Answer: the low air pressure reducing CO2 solubility
The differences between the airplane and standard cruising altitude are air pressure. When you are on the higher ground, the air pressure should be lower since there is less air above your head.
In a place with less air pressure, the gas solubility will decrease. Bubbles appeared if gas solubility is lower than the gas concentration. Assuming the beverage concentration is same, then it will be much more bubble appeared in an airplane because the gas solubility is lower.
