Which statement regarding chronic myeloid leukemia (CML) is a true statement?1. It is not seen in children.2. It represents 30% of all cases of leukemia.3. The average age of onset is older than 70 years.4. Affected persons carry the Philadelphia chromosome.

Answer is 4. Affected persons carry the Philadelphia chromosome.

Explanation:

The Philadelphia chromosome got its name from the city where it was discovered in 1960 by Nowell and Hungerford.

The Philadelphia chromosome is known to be an abnormal chromosome, which is found sometimes in the leukocyte. It is known to be responsible for causing chronic myeloid leukemia,CML.

The chronic myeloid disorder is the cancerof the white blood cell, i.e the leukocytes.

It  occurs in this leukemia. CML occurs occasionally in children and adolescents.  represents approximately 15% of all cases of leukemia in the US. The average age of onset is between 40-50 years.

cells use diffusion to get substances in and out of themselves. that diffusion will occur across the cell membrane or the outer covering of the cell. because we are talking about the surface of the cell, surface area and volume are  important factors here. as a cell increases in size, its surface area and volume increase as well.  we call that the surface area to volume ratio (sa: vol).  but the catch is that  volume increases at a greater rate than surface  area. in other words, as a cell gets bigger, the sa: vol gets smaller. so a really small cell like bacteria is mostly cell membrane (surface) with very little contents (volume). a really big cell like an egg, is mostly insides with a super thin membrane. so what ends up happening is that the cell cannot efficiently diffuse all of the stuff it needs in/out to survive. therefore cell size is limited to about 100mm. so how do we make organisms bigger than 100mm? cells divide! by dividing and becoming multicellular, organisms are able to grow!   check out the diagrams i attached to see the effect of sa: vol. i hope this ! good luck!