Final answer:
The synaptonemal complex is fully formed during the pachytene stage of meiosis prophase I.
Step-by-step explanation:
The statement is true. The synaptonemal complex is fully formed during the pachytene stage of prophase I in meiosis. During this stage, homologous chromosomes come together and align precisely, forming a lattice-like protein structure called the synaptonemal complex. The synaptonemal complex holds the chromosomes tightly together and allows for the exchange of genetic material through crossover.