What is a Cluster of cells implanted in the uterus?

A cluster of cells implanted in the uterus refers to a blastocyst, which is the early stage of embryonic development following fertilization. After the sperm fertilizes the egg, the resulting zygote undergoes several divisions and forms a blastocyst, which then travels to the uterus and implants into the uterine lining. This implantation is crucial for establishing a pregnancy, as it allows for the exchange of nutrients and waste between the developing embryo and the mother's blood supply.