Explain why I needed a bone marrow transplant to treat her leukemia and explain why doctors used cord blood as the source of blood stem cells for her bone marrow transplant

Leukemia occurs in the bone marrow.

Explanation:

A bone marrow transplant is needed to treat her leukemia because leukemia occurs in the bone marrow. Leukemia is a type of blood cancers that usually begin in the bone marrow and result in high numbers of abnormal blood cells which only be treated when the infected bone marrow is replaced with healthy bone marrow. Doctors used cord blood as the source of blood stem cells for bone marrow transplant because cord blood has stem cells which has the ability to treat leukemia.

Answer is A) characterized by four seasons.

Deciduous forest is characterized by the trees whose leaves fall seasonally.  Trees of this forest grow in areas where there are four distinct seasons and having annual rainfall between 750 to 1,500 mm. The fallen leaves from the trees provide a regular source of organic matter to the soil. The trees in deciduous forest is dominated by broad leaf trees such as oaks, maples, beeches. Besides these trees shrubs and perennial herbs also found in abundance.