A membrane that allows only some materials to move in and out of the cell is B. Semipermeable.
An element's atomic number is the amount of protons (positively charge subatomic particle found in the atoms nucleus) present in one atom of that element.
I guess you forgot to add the picture or so.
Based on the Complementarity of the 4 nucleotides, The thymine must always be placed in front of the Adenine, and the Cytosine must always be placed in front of the Guanine.
Any change in this rule causes the deformation of the DNA, and can sometimes cause fatal diseases like the melanoma (skin cancer) etc...
Hope this Helps! :)
