Purines and pyrimidines are the nitrogenous bases found in the genetic material. Purines include Adenine (A) and Guanine (G) while pyrimidines include Thymine (T), Cytosine (C) and Uracil (U). Purines always pair with pyrimdine and keeps the strands of DNA at the same distance. THIS IS BECAUSE, PURINES ARE DOUBLE RINGED STRUCTURES AND PYRIMIDINES ARE SINGLE RINGED STRUCTURES. PAIRING OF PURINES WITH PYRIMIDINES MAINTAIN THE STRUCTURE OF THE DNA.
Answer:
A
Explanation:
The organism inherits traits from its parents through the genes that they pass down.
A reproductive barrier preventing interbreeding because the two species mate during different times of the year is called a temporal isolation. It basically means being isolated in time. It is a mechanism in which two species cannot mate since their mating seasons are at different period of time. For example the American toad breeds early in summer season. On the other hand, the Fowler toad would mate late in summer season. Due to this difference, they are prevented to interbreed.
Answer:
A biological system is a complex network which connects several biologically relevant entities. Biological organization spans several scales and are determined based different structures depending on what the system is. Examples of biological systems at the macro scale are populations of organisms.
Explanation:
Chromosomal crossover, or crossing over, is the exchange of genetic material during sexual reproduction between two homologous chromosomes' non-sister chromatids that results in recombinant chromosomes. ... Crossing over is described, in theory, by Thomas Hunt Morgan.