What is affected by the electrical signal sent by the fourth structure of the reflex arc?(This will be the fifth structure in the arc.)

The effector organ is affected by the fourth structure of the reflex arc.

Explanation:

When talking about the reflex arc, we refer to the sequence of events that occur for the body to react to an external stimulus.

In general terms, the peripheric nervous system receives information from a stimulus coming from the external environment. This information is sent to the central nervous system, where it is processed. From the CNS, another signal is sent as a response to the stimulus. This mechanism is known as the reflex arc.

Five elements compose the reflex arc, which are receptors, three types of neurons, and effectors.

There are three types of neurons involved in the mechanism:

•Afferent or sensorial neurons

•Interneurons

•Efferent or motor neurons

Action:

The stimulus reaches the body and is received by the specialized sensory receptors. Information is received by these receptors and converted from stimuli energy (temperature, pressure, light, etc.) to action potential energy. Afferent neurons, placed in the dermis and epidermis, receive information from receptors, react and send the information to the central nervous system as nerve impulses.

Once the information reaches the central nervous system, it is processed by the interneurons that analyze it before sending a response. Interneurons manage many sensorial signals, evaluate and compare them, and send a motor response.

Efferent neurons receive information from the interneurons and are stimulated to carry these new signals from the central nervous system to the cells of the effector organs. The effector organ can be a muscle or a gland.

Finally, the target tissue responds to the stimulus as a contraction, if it is a muscle, or as hormones release if it is a gland.

The correct answer would be Genetic drift greatly affects small populations, but large populations can recover.

Genetic variation is one of the mechanisms of evolution due to which the allellic frequency of a population changes as a result of random sampling of the organisms.

It may result in the loss of the genetic variation or alleles in a population.

Its results are maximum when the population size is small as they are more susceptible to the random changes.

In addition, its effects are increased when the population size is adversely reduced due to a natural disaster.