The hormone called human placental lactogen (hPL) is a hormone secreted by the placenta, which functions to supply nutrients and oxygen to the growing fetus in the womb.
The human placental lactogen is produced to help in the efficient use of ingested food substances in the production of energy (metabolism). This indirectly helps to nourish the placenta because if the mother efficiently converts food into nutrients, the placenta is also adequately nourished.
If you're looking for a quote regarding using sunlight as a source or energy, a quote by Maria Telkes would be '"Sunlight will be used as a source of energy sooner or later..." she said. "Why wait?"'
