The correct option is BY CONDUCTING EXPERIMENTS THAT EXPOSE THEIR PROPERTIES.
Scientific investigations are always ongoing in all parts of the world, scientists strive to build on existing knowledge by carrying out more experiments that are targeted at obtaining more information above that which is already known.
        
             
        
        
        
Answer:
A. chromosomes
Explanation:
Chromosomes are structures found in the center (nucleus) of cells that carry long pieces of DNA. DNA is the material that contains genes and is the building block of the human body.
Chromosomes come in pairs. Normally, each cell in the human body has 23 pairs of chromosomes (46 chromosomes in all), of which half comes from the mother and half from the father.
 
        
             
        
        
        
Answer:
4) to aid in the transmission of an impulse, neurotransmitters are secreted into a synapse
 
        
             
        
        
        
The metric system is a system of weights and measures that was first applied in 1795 in France. Experts everywhere the world use it as the international standard to evidently communicate data. The significance are the following:
•	SIMPLICITY which is the metric system is much simple than the english system because it uses a standard conversion influence for all units. 
•	FAMILIARITY which is almost every nation excluding the united states has accepted the metric system as its official system of weight and measures. 
•	UNIFORMITY which is scientists use the metric system so all experiments are conducted using the same weights and measures. 
•	HISTORY which is the general session on weights and measures formally chosen six metric units to be used as international standards in 1954 and in 1960 and the meter was formally distinct established on the wavelength of light from krypton atoms.
•	TYPES which is the metric system use meters for space, grams for mass, liters for volume and candelas for light.