If the Na+ voltage-gated channels in a muscle cell open, the Na (sodium) ions rush inside the muscle cell and makes the cell more positive as Na ions carry positive charge on it. Due to the entry of positively charged ions inside the cell, the cell becomes less negative and more positive. This is called depolarization of cell.
Answer:
species
Explanation:
According to the most widely used species definition, the biological species concept, a species is a group of organisms that can potentially interbreed, or mate, with one another to produce viable, fertile offspring.
I'm pretty sure it's heterozygous Rr.
Answer:
B) The "lub-dub" sound originates from blood turbulence through the heart.
Explanation:
The systole and diastole in the heart produce the lub and dub sound in the heart.
The systole represents the contraction of both left and right ventricles and pumps the blood to the body and the right ventricle to the lungs. This involves the opening and closing of the valves. The closing of the atrioventricular valves produces lub sound.
At the end of the systole or ventricular contraction or when the blood has been pumped to the aorta and the pulmonary valves then the semilunar valves present in the aorta and pulmonary closes. This produces a sound dub.
Therefore,lub dub is associated with the physical contraction of the heart but not the turbulence of the blood.
Thus, the selected option is the correct answer.
