Chromatid (Greek khrōmat- 'color' + -id) is one copy of a newly copied chromosome which is still joined to the original chromosome by a single centromere.
Before replication, one chromosome is composed of one DNA molecule. Following replication, each chromosome is composed of two DNA molecules; in other words, DNA replication itself increases the amount of DNA but does not increase the number of chromosomes. The two identical copies—each forming one half of the replicated chromosome—are called chromatids.[1]During the later stages of cell division these chromatids separate longitudinally to become individual chromosomes.[2]
Chromatid pairs are normally genetically identical, and said to be homozygous; however, if mutation(s) occur, they will present slight differences, in which case they are heterozygous. The pairing of chromatids should not be confused with the ploidy of an organism, which is the number of homologous versions of a chromosome.
Chromonema is the fibre-like structure in prophase in the primary stage of DNA condensation. In metaphase, they are called chromatids.
Answer:
The mechanism that Darwin proposed for evolution is natural selection. Because resources are limited in nature, organisms with heritable traits that favor survival and reproduction will tend to leave more offspring than their peers, causing the traits to increase in frequency over generations.
The reason that natural selection is important is that it's the central idea, stemming from Charles Darwin and Alfred Russel Wallace, that explains design in nature. It is the one process that is responsible for the evolution of adaptations of organisms to their environment.
Explanation:
hope this helps
Anton van Leeuwenhoek :-))
Answer:
false because atom are the smallest classification of matter
