A particular diploid plant species has 48 chromosomes, or two sets. A mutation occurs and gametes with 48 chromosomes are produced. If self-fertilization occurs, the zygote will have set(s) of chromosomes.

4 sets

Explanation:

Both gametes will each have 48 chromosomes (2 sets). So if fertilisation were to occur, two of those gametes (both with 2 sets each) the zygote will have 4 sets.

for example, no new evidence will demonstrate that the earth does not orbit around the sun (heliocentric theory), or that living things are not made of cells (cell theory), that matter is not composed of atoms, or that the surface of the earth is not divided into solid plates that have moved over geological timescales .