Firstly they are not membranes and they are villi's which increase the surface area during digestion
What are you trying to ask?
The distinguishing characteristics of the free living members of sarcodina are:
1. These are pseudopods (function in locomotion) which makes it the extentions of protoplasm.
2. These have both a clear ectoplasm and a granualated endoplasm.
3. These have nucleus both food vacuoles and contractile vacuoles.
<span>Atherosclerosis is a common cause, because there is a lack of blood flow in the person's body, and this can cause a male to be impotent.
Diabetes is also a common cause because once again it causes less blood flow.
In a younger man, a cause could be anxiety. This is because nervousness and being anxious can lessen blood flow.
If you have choices, I suggest choosing one that has to do with less blood flow happening, which that is the main cause.
I hope that this could possibly help you with your studies, and have an amazing day. If you have any more questions, send me a pm. </span>