Answer:
demospongi and sclerospongi are two classes of sponge
Explanation:
Sponges have/are:
Body with cells arranged around pores, canals and chambers for the passage of water.
Skeletal structure of spicules and/or spongin.
All aquatic, mainly marine.
Filter feeders.
Sessile adults; sessile, planktonic larvae.
Sexual and asexual reproduction.
Gas exchange is by diffusion.
the plant tissue that transport water and nutriens are phloem and xylem
Answer:
recognizes a hormone’s chemical structure
Explanation:
In living systems, chemical messengers called hormones are secreted into the body via the bloodstream or ducts by certain glands called endocrine glands e.g pancreas, hypothalamus etc. These hormones are meant to effect a physiological change in certain cells called TARGET CELLS.
In biology, a target cell is any receiving cell that has the ability to respond to signals and messengers like hormones. This responding ability of hormones is due to the possession of specific receptor sites for the specific hormones. The receptor on a particular target cell recognizes that specific hormone's chemical structure, hence, will only respond to it.
For example, an insulin hormone secreted by the pancreas will only be responded to by a target cell that recognizes the chemical structure of the insulin protein using its receptor molecule.
<h2>Answer:</h2>
It is a true statement.
Explanation:
The plan cell wall is composed of 3 layers or 3 types of walls:
- Primary cell wall.
- Secondary cell wall.
- Middle lamella.
Between primary and secondary there is middle lamella.
These layer make it a laminated two layer structure.
