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:
<u>They produce the materials needed by the sperm to travel to the egg</u>
Explanation:
Seminal vesicles are glands located near the distal end of the vas deferens. They are responsible mainly for the secretion of seminal fluid as the sperm are moved along towards the ejaculatory duct. The seminal fluid contains a substance which stimulates the sperms. The seminal fluid also contains simple sugars e.g. fructose which provide nourishment for the sperms.
Answer:
This is a physical change.
Explanation:
A change in state, such as a change from solid to a liquid, is a physical change.