How does the cell membrane of a tube worm maintains a stable environment

The cell membrane of a tubeworm is selectively permeable and they prevent minerals in the water from flowing it in the cell of tube worms. By doing this the cell membrane protects the cell from any osmotic damage. By selectively preventing these minerals it maintains the stable environment in the cell

during the process of dna replication, brdu can replace thymidine and incorporate into the newly synthesized dna, cell proliferation thus can be reflected in the extent of brdu incorporation.

the answer is sex-linked recessive.