XO type of sex determination can be found in:

📌 Concept:
– Sex determination is the mechanism that determines the biological sex of an individual.
– Henking (1891) observed a nuclear structure and named it X-body later named X- chromosomes.
– He also observed that after spermatogenesis, half of the sperms receive this X- body, and half of them did not.
– As the X-chromosome is involved in the sex determination process, it is termed a sex chromosome.
– The other chromosomes that are not involved in sex determination are known as autosomes.

✅ Explanation:
Option 1: 
-XX/XY type – The females possess a pair of X-chromosomes, while the males possess one X-chromosome and one Y-chromosome. Example. – Man, Monkey.
Option 2: 
-XX/XY type – The females possess a pair of X-chromosomes, while the males possess one X-chromosome and one Y-chromosome. Example. – Man, Drosophila.
​Option 3: 
-ZW/ZZ type: In this type, the females produce 2 different types of gametes while the males produce a single type of gamete. Females have one Z and one W chromosome, whereas males have a pair of Z chromosomes besides the autosomes.  Example: Birds.
Option 4: 
-XX/XO type – The females possess a pair of X-chromosomes, but the males possess only one X-chromosome, thus having one less chromosome than the females. Example. – Grasshopper. 

🔴 Additional Information::
-Male heterogamety: In XO type and XY type, males produce two different types of gametes, (a) either with or without X-chromosome or (b) some gametes with X-chromosome and some with Y-chromosome. Such types of sex determination mechanisms are designated to be an example of male heterogamety.
-Female heterogamety: In these organisms, the females have one Z and one W chromosome, whereas males have a pair of Z-chromosomes besides the autosomes. Two different types of gametes in terms of the sex chromosomes are produced by females, i.e., female heterogamety.