If ova and spermatozoa unite in fertilization and form a diploid zygote, then what are united in fertilization for form a diploid zygote?

Answer choices:
- h2o
 - Veins and arteries.
 - produce offspring
 - Most plants
 - joined
 - ova and spermatozoa
 - glucose and fructose
 - Organic compounds

 

      ova and spermatozoa    