Aquatic plants can live in the benthic zone of shallow lakes because a. they live on decaying organisms b. the bottom is always c. they cannot tolerate salt water d. sunlight reaches the bottom

The correct answer is option d, that is, the sunlight reaches the bottom.  

A community of organisms that thrives on, in, or close to the seafloor is known as the benthic zone. The species living in the benthic zone are known as benthos. The species dwells at the bottom of the freshwater bodies like rivers and lakes.  

The plants, which lives in the higher levels of the benthic zone are known as phytobenthos. However, these plants require sunlight in order to perform the process of photosynthesis. Therefore, these bottom-thriving plants are found in water, which is shallow enough for light to reach towards them. These plants are considered as benthic producers that signifies that they utilize the energy from the Sun to generate tissues of plants, which can be consumed by other species.  

c.) polymerase chain reaction

- "unlike the original dna fingerprinting method, dna profiling does not use restriction enzymes to cut the dna. instead it uses the polymerase chain reaction (pcr)? to produce many copies of specific str sequences. pcr is an automated procedure that generates lots of copies of a specific sequence of dna."