Answer:
Many scientists favor the RNA world hypothesis, in which RNA, not DNA, was the first genetic molecule of life on Earth. Other ideas include the pre-RNA world hypothesis and the metabolism-first hypothesis. Organic compounds could have been delivered to early Earth by meteorites and other celestial objects
Answer:
Please find the explanation below
Explanation:
Sexual reproduction is the kind of reproduction that requires two organisms (male and female) to form an offspring. The male organism produces gametes called SPERM while the female organism produces gametes called EGG. These two gametes come together in a process called FERTILIZATION to produce a zygote, which develops into an offspring.
In sexual reproduction, gametes are produced by organisms involved via a process called MEIOSIS. Meiosis, however, reduces the chromosome number of the gametes by half. However, one process unique to only meiosis and sexual reproduction is called CROSSING OVER.
Crossing over is the process whereby chromosome segments is exchanged between non-sister chromatids of homologous chromosome. This process causes a recombination of chromosomes (alleles) in such a way that the gametes will be genetically different from the parent organisms (genetic variation). According to this question, sexual reproduction leads to more genetic variation than asexual reproduction due to the process of CROSSING OVER that occurs in sexual reproduction.
