I is answer. Don't open link. It is most likeky unsafe.
Answer:
The area under a speed-time graph represents the distance travelled.
Effacement: The cervix – which is normally long and thick, measuring about 1-2 inches, starts to get shorter and thinner. This process is known as effacement. As the cervix gets more and more effaced, it gets shorter and shorter and “pulled up” into the lower part of the uterus.
Dilation: At the same time, the cervix softens and begins to open up – known as dilation. This widening, allows a smooth passage for the baby’s head and the rest of the body from the uterus into the vaginal canal.
If both of those sexual partners are faithful to each other, and only have sexual relations with one another, then there isn't a high probability that either of them is going to get HIV. If they want to be sure, they should use protection, such as condoms, to prevent getting HIV through body fluids. And they should always be honest with each other in case one of them has that disease.