Q. Twins are born to a family that lives next door to you. The twins are a boy and a girl. Which of the following must be true?
A) They are monozygotic twins.
B) They are fraternal twins.
C) They were conceived through in vitro fertilization.
D) They have 75% identical genetic content.
Explanation
[Solution by Claude - not from source] Monozygotic twins share the same genotype and sex, so a boy-girl pair must be dizygotic (fraternal). Answer (2), as in the answer key.
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.