<span>Gill arches of jawless fishes</span>
Answer:
The process that occurs in the structures marked with X is the Krebs cycle (last option).
Explanation:
The Krebs cycle is a process by which energy in the form of ATP is produced from pyruvate molecules obtained by transformation of glucose, which occurs in the mitochondria, marked with X in the diagram (see image).
The mitochondria is a specialized organelle, whose function is the production of energy within the cell. It has a membrane on the outside that allows the passage of proteins, energetic substrate and ions, and inside it crests are formed where the energetic synthesis takes place.
Learn more:
Krebs cycle brainly.com/question/7220096
Answer:
b. neurotransmitters
Explanation:
Neurotransmitters are chemical substances released by axons that are the terminal parts of neurons, neurotransmitters are stored in membrane-bound synoptic vesicles at axon terminals. The neurotransmitter discharge happens when a nerve impulse reaches the end of the axons
Answer: Because scientists often repeat one or more steps several times.
Explanation: The scientific method is described as nonlinear because scientists often repeat one or more steps several times. The correct option among all the options that are given in the question is the second option or option "b".