Cardiac Conduction System is a group of specialized cardiac muscle cells in the walls of the heart that send signal to the heart muscles causing it to contract.
Here is one possible answer:
Do allergen-free pillows cause fewer germs to grow
Photosynthesis is necessary for providing energy for an ecosystem. Plants produce energy by the sun. This allows animals to eat the plants, getting its energy. Then predators can eat those animals. When all of these organisms die, then decomposers eat the decaying matter.
The answer is D
Explanation: In humans, recessive sex-linked traits generally occur on the X chromosome. Since males are (XY), they will inherit only one sex-linked allele on their X chromosome.
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