What is the definition of a zygote?

A zygote is specifically defined as a fertilized egg, which occurs when a sperm cell successfully joins with an ovum (egg cell). This process marks the initial stage of development for a new organism, combining genetic material from both parents.

At this stage, the zygote contains all the necessary genetic information to begin the process of cellular division and differentiation, eventually developing into an embryo. Understanding this concept is critical in the study of biology, especially in reproductive biology, where the life cycle begins at the zygotic stage.

The other options represent different stages or entities in the reproductive process or offspring development, but they do not accurately describe the zygote itself. For instance, a mature ovum is an egg that has not yet been fertilized, while an unfertilized egg refers to an ovum that remains unjoined with sperm. Meanwhile, the phrase "any offspring produced" encompasses multiple developmental stages and types of progeny, which is broader than the specific term 'zygote'.