Answer:
Most cells within planarians tend to be very close to their gastrovascular cavity, in addition to their external environments. Also, planarians have the ability for oxygen and carbon dioxide to diffuse through the cells on their body walls: this makes it unnecessary for these varieties of flatworms to need a dedicated bodily system.
I think the deficiency of dedicated respiratory and circulatory systems in Planarians does not cause a problem because none of their cells are far removed from the gastrovascular cavity or from the external environment. Planarians are free-living flatworms and form the class Turbellarians in the Phylum Platyhelminthes. Flatworms have three tissue layers, that is the ectoderm, mesoderm, and endoderm.
hope this helps!!!!!....
Explanation:
A genetic mutation is a permanent modification in the DNA sequence of a gene to what is found in most people.
Its most likely B because its Skeleton is its structure (?)
Answer:
regulation of the diameter of blood vessels and control of blood pressure
Explanation:
Skeletal muscles are the multinucleated muscles with striations and are attached to the bones (skeleton). The main function of skeletal muscles is to generate the voluntary movement of the body or body parts. The skeletal muscles of face, rectum, and urinary bladder generate their voluntary movement as per the will of the organism. On the other hand, blood vessels are lined with smooth muscles with spindle-shaped cells.
For example, the muscles present in the subcutaneous layer of the skin of the face are responsible for various facial expressions. Contraction of these facial muscles brings about the movement of skin of the face to generate a wide variety of emotions. Smooth muscles of blood vessels are involuntary in nature.
Vasodilation and vasoconstriction as brought about by smooth muscles of blood vessels are regulated by the autonomic nervous system. Under the conditions of lower blood pressure, contraction of smooth muscles of blood vessels restore the reduced blood pressure. On the other hand, when the blood pressure rises above the normal range, the smooth muscles of blood vessels relax to dilate them and to lower down the blood pressure.
