Given a scientific passage and an answer, generate a question for the given answer.
--------
Question: Passage: Imagine walking in the forest in Figure below . The towering trees have been growing here for hundreds of years. It may seem as though the forest has been there forever. But no ecosystem is truly static. The numbers and types of species in most ecosystems change to some degree through time. This is called ecological succession. Important cases of ecological succession are primary succession and secondary succession. Answer: ecological succession

Answer: The numbers and types of species in most ecosystems change to some degree through time and this is called?

Question: Passage: Diagram of a typical prokaryotic cell. Among other things, prokaryotic cells have a plasma membrane, cytoplasm, ribosomes, and DNA. Prokaryotes do not have membrane-bound organelles or a cell nucleus. Answer: not membrane-bound

Answer: What are unique about prokaryotic cells' organelles?

Question: Passage: Gastrointestinal and Urinary Adjustments In adults, the gastrointestinal tract harbors bacterial floratrillions of bacteria that aid in digestion, produce vitamins, and protect from the invasion or replication of pathogens. In stark contrast, the fetal intestine is sterile. The first consumption of breast milk or formula floods the neonatal gastrointestinal tract with beneficial bacteria that begin to establish the bacterial flora. The fetal kidneys filter blood and produce urine, but the neonatal kidneys are still immature and inefficient at concentrating urine. Therefore, newborns produce very dilute urine, making it particularly important for infants to obtain sufficient fluids from breast milk or formula. Answer: beneficial bacteria

Answer:
The first consumption of breast milk or formula floods the baby's gastrointestinal tract with what?