Answer:These contractile elements are virtually identical to skeletal muscle. ... (a) Cardiac muscle cells have myofibrils composed of myofilaments arranged in sarcomeres, ... The refractory period is very long to prevent the possibility of tetany, a ... At this point, the calcium ion channels close and K+ channels open, allowing outflux ..
Explanation:
Response would be an epinephrine pen, which basically derived of a triple dose of epinephrine...
B. Stomata. These are the holes in leaves that gases pass through. So, while leaves have something to do with it, petals do not, so D is close but wrong answer.
Answer;
Sodium (Na)
A single sodium atom has 11 protons, 11 electrons, and 12 neutrons.
Explanation;
For any neutral atom, the number of protons is the same as the number of electrons. If an atom loses or gains electrons, it is called an ion.
A sodium atom contains 11 protons, so its atomic number is 11. Mass number is the total of the protons and neutrons together, thus sodium has a mass number of 23.
The first answer is species and the second answer is C