Correct Answer: (a) hormonal and emotional stimuli also causes sweating
Solution:The conjunction 'or' will be replaced with the conjunction 'and' as it is used to connect two or more words. Since both the factors 'hormonal stimulus' and 'emotional stimulus' are responsible for sweating, we need to use the conjunction 'and'. The given sentence is an example of Simple Present Tense as the prepositional phrase is given in Simple Present tense. Hence, hormonal and emotional stimuli also causes sweating' is the most appropriate answer.