सूर्य के प्रकाश के संपर्क में आने पर हमारी त्वचा की किस परत में विटामिन D का निर्माण होता है?

Which digestive hormone inhibits both gastric secretion and motility, stimulates insulin release, and is secreted mainly when fat is present in the duodenum?

The repeated sequence of gradual onset of apnoea followed by gradual restoration of respiration is called ________.