How many cells are located at the chalazal end of the embryo sac?

Three

The correct answer is c) Three.

At the chalazal end of the embryo sac, there are three cells. These cells are known as the antipodals. The antipodal cells are positioned opposite to the micropylar end of the embryo sac, where the egg apparatus is located.

The antipodal cells are often found at the far end of the embryo sac, near the region of the ovule called the chalaza. They are typically located opposite to the synergids and the egg cell of the egg apparatus.

The function of the antipodal cells in the embryo sac is not entirely understood and varies among different plant species. Their exact role in plant development and reproduction is still a subject of research and investigation. However, some proposed functions include providing support and nutrition to the developing embryo, assisting in the breakdown of endosperm after fertilization, and potentially playing a role in embryo sac degeneration or nutrient storage.

While the specific functions of the antipodal cells are not fully elucidated, their presence within the embryo sac demonstrates the complex cellular organization and specialization that occurs during the development of the female gametophyte in flowering plants.