* Tetrad complexes: These are formed during meiosis, the process of cell division that produces gametes (sperm and egg). A tetrad is a structure made up of two homologous chromosomes (one from each parent), each with two sister chromatids.

* 2n = 4: This means the organism has a diploid number of 4 chromosomes. In other words, it has two sets of chromosomes (one set from each parent).

Here's how we figure out the number of tetrads:

1. Homologous pairs: An organism with 2n = 4 has two pairs of homologous chromosomes.

2. Tetrads formed: During meiosis, each pair of homologous chromosomes forms one tetrad.

3. Total tetrads: Since there are two pairs of homologous chromosomes, there will be two tetrad complexes.

Therefore, an organism with 2n = 4 will have two tetrad complexes during meiosis.