The answer is C. We can suppose that the Grey gene is "A" and Black gene is "a". So the gene of heterozygous grey fruit fly is "Aa", and the black-bodied fruit fly is "aa". After mating, the offspring can get only "a" from balck-bodied fruit fly and has equal opportunity to get a "A" or "a" from heterozygous grey fruit fly. If the gene of offspring is "Aa", it will be grey. If "aa", it will be black. So the proportion of being black is 0.5.
The answer to your question is Vegetative Propagation.
Vegetative Propagation is defined as a form of asexual reproduction of a plant. It occurs when only one "parent plant" is involved in producing an offspring that will be genetically identical to the parent.
The magnetic field of a bar magnet is the strongest at either pole of the magnet. It is equally strong at the North Pole when compared with the south pole. So I would say the answer is A.
Calcium is a chemical element with symbol Ca and atomic number 20. Calcium is a soft gray Group 2 alkaline earth metal, fifth-most-abundant element by mass in the Earth's crust. The ion Ca2+ is also the fifth-most-abundant dissolved ion in seawater by both molarity and mass, after sodium, chloride, magnesium, and sulfate.[5] Free calcium metal is too reactive to occur in nature. Calcium is produced in supernova nucleosynthesis.