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.
The nucleus intructs cells to do their activities
Its A. it prevents sperm from reaching the egg and fertilizing it.
They provide an important habitat!