Answer:
The correct answer will be option-C
Explanation:
The rhythm of the heartbeat is controlled by the pacemaker of the heart called the sino-atrial node.
The SA node generates action potentials which trigger the contraction and relaxation of the atrium and ventricles. The membrane potential generation initiates by the depolarization of the cell membrane when the L type of Ca⁺² ions opens up and calcium ions enter the cell.
This depolarizes the cell until the potential threshold is reached which lies between the -40 and -30 mV.
Thus, Option-C is the correct answer.
The unicellular and multicellular organism are different in asexual and sexual mode of reproduction.
The reproduction is the phenomenon which involves the production of an offspring by particular individuals or individuals to propagate there species. Reproduction are of two types:
1. Asexual reproduction: In asexual reproduction, they does not involve the fusion of gametes. The unicellular organism reproduce mainly by binary fission. In this, a single cell divides into two daughter cell. The daughter cell completely resembles their parent. It involves only one parent.
2. Sexual reproduction: In sexual reproduction, there is a fusion of gametes that brings changes in genetic combination. The germ cell undergoes meiosis that produces haploid gametes that fuse to form new individuals. It involves either one or two parents.
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Answer: they have to maintain homeostasis, so they remove waste to do so..
