Shall I use "without doubt" or "without a doubt" to start my sentence in an essay?

Lesson 10: crossing borders: unit test “borders” 1.what does the mother’s refusal to state her nationality as canadian or american signify? a)that she resents governmental interference with her life b)that she identifies with neither country c)that she comes from somewhere else d)that she is stubborn and proud 4.the author’s chosen visual images,sensory details, and dialogue all convey a particular feeling in “delfino ii: diez in the desert.” thus feeling is known as: a)tone b)mood c)pathos 5.compare and contrast the poem “mexicans begin jogging” and the story “delfino ii: diez in the desert.” a)both are written about similar themes (immigration), but the story has a more serious mood than the poem b)both focus on mexican immigrants, but the story has a lighter tone than the poem. c)both main characters are afraid: diez is afraid of being caught smuggling people over the border, and soto is afraid of being caught working illegally. d)the tone in both selections is similar, but the subject matter differs slightly. 15. the tone of the poem “ka’ba” versus the tone of the poem “harlem ii” might be described as a)grateful vs ungrateful b)certain vs doubtful c) hurtful vs defeated d)safe vs dangerous