During the preschool examination of a 4-year-old boy, you are unable to palpate his testes within the scrotal sac. his parents state that previous exams have been normal, and that the testes are clearly visible during baths. what is the most likely explanation? a. a chilly examination room or your cold hands have activated the cremasteric reflex. b. the testes may have migrated back up into the boy's abdomen since the last examination. c. because he does not trust you, the boy is deliberately causing his testes to retract close to his body. d. the parents' observations are probably incorrect.

a. A chilly examination room or your cold hands have activated the cremasteric reflex.  

Explanation:

           Cremasteric reflex is the superficial reflex which is found only in human males that is revoked when  inner thigh is stroked. Stroking the skin activates the cremaster muscle and it helps to contract ipsilateral testicle up towards the inguinal canal.

          Thus in the context, in the preschool exam, the examiner could not feel the baby's testes but his parents claims that the testes are visible while having bath and are normal in size. The examiner could not palpate the baby's testes because the the room was cold enough  or the examiner's hand was cold enough which activated the cremasteric reflex and it makes the testes to pull up.

Hence the correct option is (a).

question - in 1827, john walker, a druggist in a small english town, tipped a splint with sulphur, chlorate of potash, and sulphid of antimony, and rubbed it on sandpaper, and it burst into flame. the druggist had discovered the first friction-chemical match, the kind we use to-day. it is called friction-chemical because it is made by mixing certain chemicals together and rubbing them. although walker's match did not require the bottle of acid, nevertheless it was not a good one. it could be lighted only by hard rubbing, and it sputtered and threw fire in all directions. in a few years, however, phosphorus was substituted on the tip for antimony, and the change worked wonders. the match could now be lighted with very little rubbing, and it was no longer necessary to have sandpaper upon which to rub it. it would ignite when rubbed on any dry surface, and there was no longer any sputtering. this was the phosphorus match, the match with which we are so familiar. according the paragraph what was the benefit of the new phosphorus match? it burst into flame when rubbed on sandpaper. it was made by mixing chemicals. it could be ignited on any dry surface. it threw fire in all directions.

answer - matches required natural chemicals