Answer: Each chromosome actually consists of two sister chromatids, which are joined together at a centromere. ... During this process, sister chromatids separate from each other and move to opposite poles of the cell. This happens in four phases, called prophase, metaphase, anaphase, and telophase. Homologous chromosomes are two pieces of DNA within a diploid organism which carry the same genes, one from each parental source. In simpler terms, both of your parents provide a complete genome. Each parent provides the same 23 chromosomes, which encode the same genes. Sister chromatids are two identical copies of the same chromosome formed by DNA replication, attached to each other by a structure called the centromere. During cell division, they are separated from each other, and each daughter cell receives one copy of the chromosome. Spindle fibers are filaments that form the mitotic spindle in cell division, i.e. mitosis and meiosis. They are chiefly involved in moving and segregating the chromosomes during nuclear division. Spindle fibers are made up of microtubules. In meiosis. Each pair of chromosomes—called a tetrad, or a bivalent—consists of four chromatids. At this point, the homologous chromosomes exchange genetic material by the process of crossing over (see linkage group). The tetrad occurs during the first phase of meiosis. It is the foursome of chromatids that forms when replicated homologous chromosomes align. It must be formed for crossing over to occur. It is broken apart when the homologous chromosomes separate in meiosis I.
Explanation:
Natural selection affects undesirable traits, because as time pass on, the undesirable traits will be lost due to the competition with the desirable traits. For an example, the Rabbits that runs slower than normal rabbits, will eventually die due to the natural selection because the normal ones will run faster than the undesirable one.
Answer:
Heterotroph obtain chemical energy from other organisms.
Explanation:
Heterotroph are the organisms which are unable to make their own food like plants. They get energy from feeding on other animals. Some animals are herbivores which feed on plants and take energy from it. Some organisms feed on herbivores are called carnivorous animals. Some animals are omnivores which feed on both plants and animals.
Examples of heterotrophic organisms are cow, lion and human etc.
Genetic variation is the answer to ur question
