Answer:
The answer is False. Although sensitive cells are <u>more abundant</u> in the <u>anterior portion</u> of the annelid´s body, in general, they are arranged in all the segments.
Explanation:
Annelids, such as the earthworm, have a variety of sensory cells:
- <u>Mechanoreceptors</u>, disposed of in groups in <em><u>each segment</u></em> of their body.
- <u>Photoreceptors</u>: Light-sensitive cells. Although they are <em><u>located in the whole </u></em>body, they are <em><u>abundant in anterior and posterior segments</u></em>, concentrated in the intern and dorsal part of the epidermis.
- <u>Humidity receptors</u> are the most sensitive cells and are <u>located in the first segments</u> of the earthworm body
- <u>Chemoreceptors</u>: sensorial cells cumulus forming a prominent tubercle with prolongations that extends through the cuticle. These tubercles form three rings <em><u>in each segment</u></em> but are especially <em><u>abundant in the anterior part</u></em> of the body.
The tegument is very rich in free nervous terminations, which functions might be tactile.
Nucleic acids are the biopolymers, or large biomolecules, essential to all known forms of life. The term nucleic acid is the overall name for DNA and RNA . They are composed of nucleotides, which are the monomers made of three components: a 5-carbon sugar, a phosphate group and a nitrogenous base.
Answer:
(1). symbiont
Explanation:
The bacterium inside the human intestine is a symbiont and the bacterium-human interaction is a symbiosis of the commensalistic type.
Commensalism is a biological interaction (symbiosis) in which members of one species -in this case the bacterium- gain benefits while those of the other species -in this case the human- neither benefit nor are harmed.