Cross section (geometry) of Earth at right. Cross-sections are often used in anatomy to illustrate the inner structure of an organ, as shown at left. A cross-section of a tree trunk, as shown at left, reveals growth rings that can be used to find the age of the tree and the temporal properties of its environment. Cross section (geometry) In geometry and science, a cross section is the non-empty intersection of a solid body in three-dimensional space with a plane, or the analog in higher-dimensional spaces. Cutting an object into slices creates many parallel cross sections. The boundary of a cross section in
The African Americans: Many Rivers to Cross series, by episode, can be found on the PBS website. "The African Americans: Many Rivers to Cross" is Henry Louis Gates, Jr.’s 13th documentary film. Reviewing the series for "The New Yorker", writer and theater critic Hilton Als wrote: “The story Gates tells in his thirteenth documentary film is an epic one, and details how enslaved black Africans became African-Americans... Gates’s quest isn’t ideological; one could call the documentary a kind of ‘Pilgrim’s Progress,’ one in which the burdens are race and property. What becomes abundantly clear vis-à-vis Gates’s lyrical investigation is the innate genius it took for African-Americans to