Two things that are required for homologous chromosomes in a tetrad to experience tension when properly connected to spindle fibers are:
1. The homologous chromosomes must be properly paired and aligned with each other. This means that the two chromosomes in the tetrad must be aligned side by side, with each gene on one chromosome matching up with its corresponding gene on the other chromosome.
2. The spindle fibers must be properly attached to the kinetochores of each chromosome in the tetrad. The kinetochores are protein structures that form on the centromeres of each chromosome, and they are responsible for attaching the spindle fibers to the chromosomes. When the spindle fibers are properly attached to the kinetochores of each chromosome in the tetrad, tension is generated that helps to pull the chromosomes apart during cell division.