instruction:
In this task you will be given an answer to a question. You need to generate a question. The answer given should be a correct answer for the generated question.
question:
The immune system is a host defense system comprising many biological structures and processes within an organism that protects against disease. To function properly, an immune system must detect a wide variety of agents, known as pathogens, from viruses to parasitic worms, and distinguish them from the organism's own healthy tissue. In many species, the immune system can be classified into subsystems, such as the innate immune system versus the adaptive immune system, or humoral immunity versus cell-mediated immunity. In humans, the blood -- brain barrier, blood -- cerebrospinal fluid barrier, and similar fluid -- brain barriers separate the peripheral immune system from the neuroimmune system, which protects the brain.
answer:
how many immune systems does the body have

question:
The XOR gate (sometimes EOR, or EXOR and pronounced as Exclusive OR) is a digital logic gate that gives a true (1 or HIGH) output when the number of true inputs is odd. An XOR gate implements an exclusive or; that is, a true output results if one, and only one, of the inputs to the gate is true. If both inputs are false (0 / LOW) or both are true, a false output results. XOR represents the inequality function, i.e., the output is true if the inputs are not alike otherwise the output is false. A way to remember XOR is 'one or the other but not both'.
answer:
why xnor and xor are called exclusive gates

question:
At the age of 11, Houston started performing as a soloist in the junior gospel choir at the New Hope Baptist Church in Newark, where she also learned to play the piano. Her first solo performance in the church was 'Guide Me, O Thou Great Jehovah'. When Houston was a teenager, she attended Mount Saint Dominic Academy, a Catholic girls' high school in Caldwell, New Jersey, where she met her best friend Robyn Crawford, whom she described as the 'sister she never had'. While Houston was still in school, her mother continued to teach her how to sing. Houston was also exposed to the music of Chaka Khan, Gladys Knight, and Roberta Flack, most of whom would have an influence on her as a singer and performer.
answer:
what inspired whitney houston to become a singer