I believe the correct answer would be B. Semipermeable means that it allows certain substances to pass through, and certain other ones to not pass through. So given all of your options, I would say that B makes the most sense. Hope this helped!
-TTL
The immune system and the nervous system maintain extensive communication, including 'hardwiring' of sympathetic and parasympathetic nerves to lymphoid organs. Neurotransmitters such as acetylcholine, norepinephrine, vasoactive intestinal peptide, substance P and histamine modulate immune activity.
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.
Differentiation->Fertilization->Gamete Production-Mitosis
<span>Fertilization->Differentiation->Gamete Production->Mitosis </span>
<span>Gamete Production->Fertilization->Mitosis->Diff... </span>
<span>Mitosis->Fertilization->Gamete Production->Differentiation </span>