Portia is loyal because she is still willing to be around and is not disturbed by Brutus's sickly state.
Answer-
As a part of Kiowa among Navajo and Pueblo people who was also being guided by his parents toward success in the larger society beyond Jemez, Momaday inhabited a complex world of intersecting cultures. The need to accommodate himself to these circumstances prepared him for the perceptive treatment of encounters with various cultures that characterizes his literary work. Examples: Momaday's formal education took place at the Franciscan Mission School in Jemez; the Indian School in Santa Fe; high schools in Bernalillo, New Mexico; and the Augustus Military Academy in Fort Defiance, Virginia. In 1952 he entered the University of New Mexico at Albuquerque as a political science major with minors in English and speech. He spent 1956-1957 in the law program at the University of Virginia, where he met William Faulkner; the encounter helped to shape Momaday's early prose and is most clearly reflected in the evocation of Faulkner's story "The Bear" (1942) in Momaday's poem of that title (collected in Angle of Geese and Other Poems, 1974). Returning to the University of New Mexico, Momaday graduated in 1958 and took a teaching position on the Jicarilla Apache reservation at Dulce, New Mexico.
I believe it is dry because of the word desert and deserts are dry. Acrid also means in the dictionary bitter or harsh.
"A" I suppose because it says it's a text so she needs the picture to visualize.