Answer:
I, II, III
Explanation:
A threshold stimulus is a stimulus that is capable to produce a response in excitable tissues such as neurons and muscle fibers. At threshold potential, the outward movement of K+ and inward movement of Na+ become equal to each other. When the potential exceeds the threshold potential, more and more Na+ enter the cell to depolarize it and to allow the opening of Na+ channels. Therefore, to fire an action potential, the threshold must be exceeded. 
Conduction of action potential is all or none phenomenon which means that either it occurs or it does not occur. As an impulse is passed by each successive part of an exon, it enters the refractory period during which there is no conduction of nerve impulse. It ensures the one-way conduction of impulse from the cell body to the axon terminal only.
 
        
             
        
        
        
Answer:
moss hornworts seed plants
Explanation: there plants that could be in the water.
 
        
             
        
        
        
Answer:
The most appropriate answer would be A sperm cell fertilizes an egg cell.
In sexually reproducing organisms including plants, life starts as a single-celled zygote which is formed by the fertilization of sperm and egg.
The zygote then divides through mitotic division to form an embryo.
After fertilization In angiosperms, the ovule matures to form seed and ovary matures to form fruit.
In gymnosperms, zygote develops into a new sporophyte.
 
        
                    
             
        
        
        
Answer: taking deep breaths 
Explanation:
Apart from reminding oneself that you are prepared for the presentation. You can carry out a physical exercise like the breathing exercise by taking several deep breaths and exhaling to reduce nervousness. Also you should be mindful that the audience is there to hear you and not to judge you. In that way you can ease out tension.
 
        
             
        
        
        
The answer would be <span>no definite shape or definite volume.</span>