For a gene with a dominant allele t and recessive allele t, what proportion of the offspring from a ttxtt are expected to be homozygous dominant

The current thought on the structure of the cell membrane is: a. a static phosphate sandwich of lipids b. a fluid-mosaic of phospholipids and proteins c. a bilayer of proteins with static lipid molecules d. an impermeable bilayer of protein molecules e. a static and permeable phospholipid single layer