In a deciduous forest hundreds of dead leaves fall to the ground each autumn...
We can figure out which type of organism breaks dead leaves and decaying matter into food by looking at the characteristics of the different types you listed.
A. Herbivore - Feeds on plants
B. Omnivore - Feeds on plants and animals
C. Carnivore - Feeds on animals
D. Saprophyte - Feeds on dead or decaying matter
Therefore, from the options presented, D. Saprophyte is the correct answer.
Oxytocin causes contractions during pregnancy, it also is the reason why mothers feel "motherly" towards their children after childbirth as there are high levels on oxytocin in the mother's blood.
Well, I cannot see your list of suggestions but I am assuming one of them would be muscles.
Muscles use a lot of energy and require a large number of mitochondria.