Dichotomous key is a tool <span> - a series of questions and choices </span>that allows the user to determine the identity of items in the natural world, such as trees, wildflowers, mammals, reptiles, rocks, and fish. The first step is observing the whole specimen you want to identify. Observing  the habitat in which it is growing,its size and  overall shape and some<span> distinguishing features. It is very important to make carefully these observations in order to use the key.</span>
        
             
        
        
        
Answer:d)introns; exons
Explanation:Introns are the non-coding portion of the DNA. They do not code for a gene that can be expressed hence the need for them to be removed from the coding genes(Exons). The exons are then joined together after the introns have been removed to create a sequence of amino acids.
 
        
             
        
        
        
Answer:
Whenever there's a decrease of blood flow to the kidney, ADH is secreted which trigger the kidneys to reabsorbed water from the urine. 
Increase ADH secretion: low volume and highly concentrated urine
Decrease ADH secretion: high volume and poorly concentrated urine (diluted)
 
        
             
        
        
        
The correct answer is: <span>oxygen is used up as algae is decomposed, reducing the amount available to other organisms. Algae require nutrients to grow, and it is well known that in many rivers, algal growth is limited by one particular nutrient, most often phosphates or nitrates. This means, as soon as there is a sizable input of nutrients into a river or lake, the algae population will grow exponentially. This dramatically changes the trophic status of a river or lake. However, the algal population will eventually exhaust the supply of nutrients, and the vast biomass of algae that grew over a short period of time will all die at the same time due to lack of nutrients. As you know, rotting organic matter uses up oxygen. This results in an anoxic aquatic environment that can kill all the other organisms living in that environment. </span>
        
             
        
        
        
Answer: Pp x Pp 
Explanation: if you do a punnet square with the parent plants then it’ll show you the right answer