Answer:
fluid-filled cavity
Explanation:
Rhynchocoel is a fluid-filled tubular cavity present in the organisms of the phylum Nemertea. This cavity lies above the intestines of these organisms in the lower body.
Nemertea is a phylum composed of worms that can be found in shallow water.
These worms have already been classified as a branch of the Flatworms (such as Planarians), with which they are often confused. But recent embryological and molecular evidence points to a phylogenetic relationship with mollusks and annelids. They remind the Flatworms to be non-segmented flat worms. But unlike these, they have a complete bowel with mouth and anus, and a closed vascular system. The article on Planarians can be accessed here.
The answer is B. A chemical reaction consists of an endothermic stage (energy taken in to break chemical bonds) followed by an exothermic stage (energy released as bonds are formed). The first stage requires this energy input, which is the activation energy. When the activation energy is reached or exceeded, the reaction will occur. Therefore as soon as this threshold is REACHED, it happens
Yeah, it's the diffusion of water (osmosis). Water will move into the cell because there is a lower water-to-sodium ratio than outside.
Based on the image, it seems that the picture is of the layers of the atmosphere. Now the B layer is the thermosphere. It is found in between the mesosphere (layer below) and the ionosphere (layer above). It extends up to 600 km high and you can find satellites and the aurora here. Temperature here is higher as the height increases and it is because of this trait, its name thermosphere was based on on. "Thermo," in Greek means heat. It overlaps with the ionosphere.
