Answer:
Cells are considered the basic units of life in part because they come in discrete and easily recognizable packages. That's because all cells are surrounded by a structure called the cell membrane — which, much like the walls of a house, serves as a clear boundary between the cell's internal and external environments.
The correct options are as follows:
1. ELECTRICAL TRANSMISSION THROUGH NEURONS AND CHEMICAL TRANSMISSION BETWEEN NEURONS [D].
Neurons, which are the nerve cells that carry nerve impulses are made up of cell body and dendrites. Electrical events propagate signals within a neuron and chemical processes transmit the signals from one neuron to the other.
2. SENSORY NEURON - BRAIN - SPINAL CORD - MOTOR NEURONS [B].
Waking up from sleep involves sensory neurons. Hearing of a strange sound is made possible by the activity of the brain. The man become alarm as a result of the message to the body from the brain via the spinal cord and running involves motor neurons.
3. MOTOR NEURONS AND SENSORY NEURONS [A].
The peripheral nervous system is one of the two components of the nervous system and is made up of the nerves and the ganglia outside the brain and the spinal cord. The neurons of the peripheral nervous system is made up of sensory and motor neurons. The sensory neurons bring signals to the central nervous system while the motor neurons carry signals out of the central nervous system.
In chemical reactions involving enzymes, the substrate proteins are huge molecules that will only react with each other if they're aligned just the right way. If they are permitted to interact with the enzymes present, the won't collide and react often enough for the reaction to do any good.The enzymes align the molecules, basically acting like "molecule shepherds," showing them the way they need to react.This speeds up the reaction greatly, making things like digestion possible. Hope this is helpful
If you compare the original DNA with the mutated DNA, the first C got “substituted” by an A after the mutation.
So the answer is (C) substitution.