I believe that on the Naive B-cell the antibodies exist as transmembrane proteins. A naive b-cell is a type of b-cell that has not been exposed to an antigen. When exposed it becomes either a memory B cell or a plasma cell that secrete antibodies specific to the antigen that was originally bound.
According to the starling law, parasympathetic effects on cardiac rate and contractility include decreasing the rate of contraction and increasing the filling time resulting in a stronger contraction.
The Frank-starling law of the heart states that the stroke volume of the heart increases in response to an increase in the volume of blood filling the heart when all other factors remain constant.
<span>A cell with a large surface area or with microvilli (which increase surface area) are specialized for absorption. Many cells have different protein markers on their surface to accept certain specific hormones and allow them into the cell, like muscle cells reacting to adrenaline. Muscle cells are long and able to contract, allowing for overall muscle contraction and body movement. </span>
<span>I guess the hormone part I mentioned applies to chemicals; endocrine cells produce hormones that other cells would not. </span>
<span>For organelles, muscle cells don't have many of the organelles that other cells do because of their very specialized functions. </span>
<span>I hope this helps, it would literally take volumes of text books to answer this question completely.</span>
Answer: D. Extinctions occur at higher rates during times of ecological stress when populations and species are poorly adapted.
