Rocks,water,pebbles = Abiotic
Fish =Biotic
Neurotransmitters, such as acetylcholine--the major neurotransmitter found in the human body, act over a short time and they are quickly removed from the synapse by enzymes (i.e. acetylcholinesterase which breaks down acetylcholine to acetyl-CoA and choline).
Secretion helps in moistening the food, making it easier to swallow and preventing oral infections.
Gestational age can also be estimated by measuring the fundal height. This is done by measuring from the pubic bone to the top of the uterus. The measurement in centimeters roughly equal to the gestational age in weeks from the last menstruation.
Answer:
Protection from UV radiation
