Answer: No
Explanation: It is beneficial if the animals that are disadvantageous doesn't reproduce so it doesn't discredit natural selection. The traits in which variation is occured are more suitable for organism to live and reproduce in the environment are preserved and are passed from generation to generation.
However, natural selection effects limited number of progeny.
A cell's nucleus contains the DNA of the organism. The DNA is the same throughout the organism, but is expressed differently to create different cells (muscles, optic cells, bone, etc.)
Sorry for the delay, hope this helps :D
MOTOR neurons control voluntary or involuntary responses of the body.
Motor neurons are nerve cells located in the spinal cord. Its axon projects outside the spinal cord to directly or indirectly control effector organs like muscles and glands.
Types of neurons according to what they detect.
1) chemoreceptors - detects chemicals
2) mechanoreceptors - detects touch
3) olfactory receptors - detects smell
4) photoreceptors - detects light
5) thermoreceptors - detects temperature