Answer:
Alpha-1
Explanation:
Adrenergic receptors are the integral proteins present in the postsynaptic plasma membranes. These receptors are activated when the neurotransmitter norepinephrine and the hormones norepinephrine and epinephrine bind to them. The alpha 1 adrenergic receptors are found in the smooth muscle fibers of blood vessels that serve the salivary glands, skin, and kidneys. These receptors are also found in the radial muscle of iris of the eye as well as in the sphincter muscles of the stomach and urinary bladder.
They exert excitatory effect and lead to contraction of smooth muscles of the blood vessels, dilation of pupil, and closure of sphincters of the bladder.
The correct answer is that mammals use a closed, double loop , four chambered heart as a circulatory system of the body.
The circulatory system of mammals is closed system that consists of four chambers, two articles and two ventricles. The deoxygenated blood comes into the heart from one loop and the oxygenated blood from other loop from the heart is circulated to the whole body. This is called as double circulation.
Answer:
zygote, fertilization
(haploid) spores, meiosis
a pollen tube
Answer:
A
Explanation:
ice's density is lower that water's density
The result which would be seen from a properly prepared negative control is nothing.
<h3>What is a Negative control?</h3>
This type of control is used to test and ensure that in the absence of the antigen we do not still get a positive reaction.
Since proper aseptic technique was practised and there was no swabbing of the surface then there would be nothing seen in the properly prepared negative control.
Read more about Negative control here brainly.com/question/7452004
