To solve this problem, we need to match the stages of meiosis with their corresponding events. Let's analyze each stage:$\newline \bullet$a. Zygotene:$\newline$ - During the zygotene stage, homologous chromosomes begin to pair up in a process called synapsis.$\newline$ - This matches with (iv) Synapsis.$\newline \bullet$b. Pachytene:$\newline$ - In the pachytene stage, crossing over occurs, where homologous chromosomes exchange genetic material.$\newline$