To find the correct label for the empty red box, let's follow the life cycle shown in the diagram step-by-step:
1.
Identify the parents: On the right side (green background), we see the "Haploid gametophyte generation." These are the small leafy plants labeled $(1n)$.
2.
Identify the sex cells: The male gametophyte produces
Sperm, and the female gametophyte produces an
Egg. Both of these are haploid $(1n)$.
3.
Follow the arrows: The arrow from the Sperm and the arrow from the Egg meet at the structure where the red box is located. This indicates that the sperm and egg are joining together.
4.
Determine the process: In biology, when a male sex cell (sperm) joins with a female sex cell (egg), the process is called
fertilization.
5.
Check the result: The arrow leaving this box points to a structure labeled $(2n)$, which grows into the sporophyte. When two haploid $(1n)$ cells join, they form a diploid $(2n)$ cell called a zygote. The process that creates this zygote is fertilization.
Therefore, the missing label describes the union of sperm and egg.
Final Answer:
Fertilization
Parent Tip: Review the logic above to help your child master the concept of bryophyte worksheet.
