I believe the term for an observable trait of an organism would be called or noted as the organism's phenotype.
Answer:
A. two haploid gametes fuse to form a diploid cell
Explanation:
Meiosis is a type of cell division. When a parent cell with "2n" chromosomes enters the process of meiosis, four daughter cells each with "n" chromosomes are formed. This occurs since homologous chromosomes separate from each other during anaphase-I. However, meiosis does not include the fusion of two haploid cells. The fusion of two haploid cells mainly occurs during the process of fertilization during which a haploid male gamete and a haploid female gamete fuse to form a diploid zygote.
Calcite is the most common rock
The organelle that acts like the brain or the control center in the cell in the nucleus.
Hope this helps!!! :D