A 53 year old man presents with increasing gastric pain and is found to have a 3 cm mass located in the anterior wall of his stomach. This mass is resected and histologic examination reveals a tumor composed of cells having elongated, spindle-shaped nuclei. The tumor does not connect to the overlying gastric epithelium and is instead found only in the wall of the stomach. The tumor cells stain positively with CD117, but negatively with both desmin and S-100. Special studies find that these tumor cells have abnormalities of the KIT gene. Which of the following is the most likely diagnosis? a. Lymphoma of mucosa-associated lymphoid tissue (MALToma)
b. Ectopic islet cell adenoma (VIPoma)
c. Gastrointestinal stromal tumor (GIST)
d. Submucosal leiomyoma ("fibroid tumor")
e. Nonchromaffin paraganglioma (chemodectoma)

The correct answer is c. Gastrointestinal stromal tumor (GIST)

Explanation:

Gastrointestinal stromal tumors (GIST) are rare neoplasms that originate from mesenchymal cells, generally express the KIT receptor (CD117) and present activated mutations of the tyrosine kinase or tyrosine kinase receptor proto-oncogene, cKIT (it is the gene that encodes KIT protein synthesis). GISTs can be located in any portion of the wall of the GI tract, but most are located in the submucosa or in the muscularis propria. Some are predominantly extramural; large ones can infiltrate neighboring organs

c. earths continental crust is thicker than its lithosphere.

because, the lithosphere is the outermost layer of the earth/ 100 km thick and is defined by its machanical properties.the lithosphere contains oceanic and continental crust that varies in age and thickness across locations and geologic time. the lithosphere is the coolest layer of the earth in terms of temperature. the term lithosphere should not be confused with the use of "geosphere" which is used to indicate all of earth systems, including the atmosphere, hydrosphere   and biosphere. the surface of the earth can be divided into the continental crust and the oceanic crust.   the continental crust is made mostly of granite while the oceanic crust is made of basalt. the average thickness of the continental crust is 25 miles and the average thickness of the oceanic crust is 5 miles.   three types of rock, igneous, sedimentary, and metamorphic, make up the surface of the earth. that's why 3 option is preferable.

weathering - colorado river carves land in arizona to form the grand canyon. cracks form in a sandstone wall surrounding a house. a marble statue near the science museum is changing color due to rainfall

erosion - after a rainstorm, soil and rock piees litter the roadways. the sand dunes in the sahara desert are changing shape.

here's your answer.