The correct answer is 2) Meiosis and differentiation of gamets
Gametogenesis is an important process of development which deals with the division and differentiation of diploid(2n number of chromosome) precursor cell to generate haploid gamets.
During gametogenesis meiotic division of diploid gametocytes occur to form haploid gamets. The haploid gamets then fuses with each other to form diploid zygote.
when the displaced particles are perpendicular to the direction the wave travels, is called a transverse wave, whereas in longitudinal wave the displace practices are parallel to the direction of the wave.
in the given image:
first image shows - longitudinal wave
second image shows - transverse wave
third image shows - longitudinal wave
fourth image shows - longitudinal wave
1) fertilization and zygote development