Answer:
every muscle cell of the motor unit is stimulated to contract.
Explanation:
Stimulus in biology can be defined as an obvious change in either the chemical or physical structure of an organism' environment (either external or internal). Thus, all living organisms (both animals and plants) respond to changes in their environment and consequently, an appropriate response or reaction is made. Also, stimulus arising from within the organism is known as internal stimulus while those from its environment are known as the external stimulus.
In organisms, the specialized cells that detect stimulus are generally known as sensory receptors while a group of these receptors is referred to as sense organ. Therefore, the senses are necessary for behavior because stimuli must be sensed in order to respond.
Stimulus control can be defined as a phenomenon that arises when a living organism responds or behaves in the presence of a stimulus and in another way in the absence of a stimulus.
For example, opening the door of a microwave oven as soon as its timer beeps.
Example II; When your body touches a hot object, you quickly move away and feel some pain subsequently. 
Action potentials generates the nerve impulse in a motor neuron.
When an action potential is generated within a motor neuron, every muscle cell of the motor unit is stimulated to contract.
 
        
             
        
        
        
Answer:
correct me if im worng but i think is Dipsacaceae
Explanation:
 
        
             
        
        
        
Answer:
B. Dominant for one trait and recessive for the other
Explanation:
using the Punnetts square for the question above, the 9 in the ration refers to a dominant for both traits such as AABB, AaBb. 
while the 3: 3 refers to a dominant for a single trait and recessive for one such as AAbb, Aabb, aaBB, aaBb
and the 1 refers to recessive for both traits such as aabb.
 
        
             
        
        
        
Answer:
Prokaryotic, and eukaryotic cells share basically four common features:
1) A plasma membrane which is known as outer covering membrane it helps to separate the interior part of the cell from its surrounding.
2) Cytoplasm which is consisted of gel like region inside the cell where other parts of the cell are found.
3) Genetic material of the cell which is known as DNA.
4) Ribosomes, which helps in protein synthesis.