Sperm penetration tests check to see whether a man's sperm can move through cervical mucus and the fallopian tubes to join with (fertilize) an egg. This test is usually done when a couple is having trouble becoming pregnant (infertility). There are different sperm penetration tests.
The idea that a boundary is shifting can be applied to different areas. A shifting frontier of science would be referring to the fact that science is always changing and growing, and always with new areas. In wartime, a shifting frontier would be an international border which is constantly being renegotiated.
The Master Shift is a Non-Profit 501(c)3 organization that provides meditations and other services to humanity, including international on the ground gatherings, financial assistance to charitable organizations around the world, educational conferences that facilitate spiritual growth, worldwide healing, and commitment to sustainability and green ...