Blank 1: Implantation
Blank 2: Blastocyst
Explanation: Blastocyst is the ball of cells with hollow space, termed as blastocyst cavity. It gets implanted on the walls of the uterus, called as endometrium. This happens on the seventh day of the fertilization, which marks the end of germinal period.
Germinal period is the time of 3-4 days when fertilized cells divide and reach the uterus for implantation.