Questions: The production of milk, called lactation, is stimulated by adrenaline prolactin estradiol oxytocin The elaboration of a notochord and a dorsal nerve chord, the key developmental event that marks the evolution of the chordates, is referred to as morphogenesis. organogenesis. gastrulation. neural crest formation. neurulation.

The answer to the first question is: prolactin.

Explanation:

• Adrenaline: Incorrect. Adrenaline, also known as epinephrine, is a hormone that prepares the body for 'fight or flight' responses and is not involved in the production of milk.
• Prolactin: Correct. Prolactin is a hormone produced by the pituitary gland that stimulates milk production (lactation) in mammals.
• Estradiol: Incorrect. Estradiol is a form of estrogen, a hormone involved in the regulation of the reproductive and menstrual cycle, but it does not directly stimulate milk production.
• Oxytocin: Incorrect. Oxytocin is a hormone that causes the milk ejection reflex (let-down reflex) but does not stimulate the production of milk itself.

The answer to the second question is: neurulation.

Explanation:

• Morphogenesis: Incorrect. Morphogenesis refers to the development of the structure of an organism and its organs, but it is a broader term that encompasses more than just the development of the notochord and dorsal nerve cord.
• Organogenesis: Incorrect. Organogenesis is the process by which the organs of an organism develop, but it is not specific to the formation of the notochord and dorsal nerve cord.
• Gastrulation: Incorrect. Gastrulation is an early phase in embryonic development that involves the formation of the three primary germ layers (ectoderm, mesoderm, and endoderm), but it does not specifically refer to the development of the notochord and dorsal nerve cord.
• Neural crest formation: Incorrect. Neural crest formation is a process that occurs after neurulation and involves the development of neural crest cells, which give rise to a variety of structures, but it is not the key event marking the evolution of chordates.
• Neurulation: Correct. Neurulation is the process during embryonic development that leads to the formation of the neural tube, which eventually develops into the central nervous system (brain and spinal cord). It also involves the formation of the notochord, a key characteristic of chordates.

Summary:

• The production of milk (lactation) is stimulated by prolactin.
• The key developmental event that marks the evolution of the chordates, involving the elaboration of a notochord and a dorsal nerve cord, is referred to as neurulation.