Sunflowers due to the fact that the top of it is entirely of nectar
Foreign invaders have proteins called antigen, which antibodies lock onto to neutralize. The foreign proteins are different from proteins in our own body, so the immune system can recognize them and finally eliminate them.
The answer would be:
B. Sequence of the bases in DNA molecules.
Here is more about your questions:
DNA contain the instructions of the traits of an organism. Most of the organism have the same DNA but what makes each different is the sequence of the DNA. The sequence gives the instructions for the production of amino acid that will produce, which in turn determines what traits will be passed on or manifested by that individual.