The evolution of sexual reproduction is a great puzzle in modern evolutionary biology. Many groups of eukaryotic organisms, especially most animals and plants, reproduce sexually. The evolution of sex between two organisms of the same species contains two related but different themes: its origin and its maintenance. However, since hypotheses for the origin of sex are difficult to test experimentally, most of the current work has focused on the maintenance of sexual reproduction. Biologists, including W. D. Hamilton, Alexei Kondrashov, and George C. Williams, have proposed various explanations for how sexual reproduction is maintained in a large set of different living things.
Answer:
C. how close earth is to the sun
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Highlighted structure is median nerve cord only.
It originates from brachial plexus from medial and lateral cords. Lateral wire best medial and lateral cords lateral and posterior cords medial cord handiest.
The medial twine is the a part of the brachial plexus fashioned with the aid of of the anterior department of the lower trunk (C8-T1). Its name comes from it being medial to the axillary artery as it passes through the axilla. the opposite cords of the brachial plexus are the posterior cord and lateral cord.
The lateral cord gives rise to the lateral pectoral nerve. The posterior wire offers upward push to the higher subscapular nerve, thoracodorsal nerve and decrease subscapular nerve. The medial wire offers upward thrust to the medial pectoral nerve, medial cutaneous nerve of the arm and medial cutaneous nerve of the forearm.
The posterior cord is part of the brachial plexus. It includes contributions from all the roots of the brachial plexus. Posterior twine. Plan of brachial plexus.
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