Which of the following shows a reduction of chromosomes by half?
male gametophyte to flagellated sperm
sporophyte to spores
male gametophyte to spores
female gametophyte to zygote

The correct answer is-  

A sporophyte can be described as the multicellular, diploid phase in the life cycle of plants and alga.

It is the dominant phase in higher plants ( such as angiosperms and gymnosperms) and undergoes alternation of generation with a haploid, gametophyte phase.

Sporophyte produces haploid spores ( having half the number of chromosome as their diploid parent cell) by a process of cell division called meiosis ( also termed as reductional cell division)

The spores fuse to form a dipolid zygote that undergoes mitotic division to produce the sporophyte again.

On the contrary, male and female gametophyte are already haploid.

Thus, second option is the right answer.

prophase: we can observe the chromosomes to coil up and condense. they become visible. nuclear membrane and envelope disintigrate.s

metaphase: chromosomes align at the center, the metaphase plate. spindle fibers attach to centromeres of the sister chromatids. they meet at kinetochores.

anaphase: sister chromatids are pulled towards each opposing centromere, set on different poles.

telophase: chromosomes are now clustered up only on either sides of the cell. nuclear membranes reform, and a new cell wall forms along the cell plate. this will lead to cytokinesis, the process that divides the cell membrane and forms the cell wall.

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