The Precambrian eon is separated from the Phanerozoic eon in the fossil record because of the sudden appearance of organisms.
Explanation:
Precambrian eon is the initial existence on earth that can be predicted by the study of rocks and remaining of fossils. It has been seen as the existence of skeleton in this era, before this era no such things has been observed, even the development of sexual reproduction.
The Phanerozoic era comes after the Precambrian era, more advanced kinds of fossils of animals had been observed in this era. Phanerozoic era period of life on earth. Large organisms sudden appearance are seen in the Phanerozoic era i.e. First dinosaurs, mammals, fishes, angiosperms,first vertebrates etc.
According to the research, the correct option is A, population genetics is the study of how allele frequencies in a population change over time.
<h3>What is population genetics?</h3>
It studies the origin, amount and distribution of genetic variability present in populations.
It explains the variation between individuals, as well as the dynamics of alleles and genotypes within and between populations.
Therefore, we can conclude that according to the research, the correct option is A, population genetics is the study of how allele frequencies in a population change over time.
Learn more about population genetics here: brainly.com/question/13049509
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Answer:
cartilaginous joints
Explanation:
The joint system is formed by the joints, which can be defined as the joining region between two or more bones. All bones in the body except the hyoid bone are articulated with at least one other bone. There are several types of joints, among them, the cartilage joints, those that have cartilage between the bones. If this cartilage is hyaline, the joint is called synchondroses; if the cartilage is fibrous, the joint is called symphyses.
The joints are responsible for holding the bones together and allowing the skeleton to move.
<span>a. direction in which they carry impulses</span>
Answer:
The only way to make a whole population evolve is through natural selection.
