The Earth comprises many spheres of subsystems, which associate with each other to develop a composite and spontaneously changing system of the Earth. The processes taking place in the system of the Earth occurs on spatial scales changing from fractions of millimeters to thousands of kilometers, and on time scales, which varies from milliseconds to billions of years.
The examples of instantaneous scales are a rotation of the Earth, breathing, an earthquake.
The examples of long-term scales are making coal and plate tectonics.
The system of the Earth is featured by various overlapping cycles in which matter is recycled again and again. The cycles involve interactions between multiple spheres and systems. The examples of cycles are rock cycle, day and night, and seasons.
Volcanoes discharge a huge concentration of particulate matter into the atmosphere. These particles function as nuclei for the development of droplets of water (hydrosphere). The rainfall, that is, hydrosphere usually upsurges after an eruption, initiating growth of the plant (biosphere). Thus, volcanoes and volcanic activities are a good illustration of system interactions.
Answer: Base pairs are formed when adenine forms a hydrogen bond with thymine, or cytosine forms a hydrogen bond with guanine. The second part of a nucleotide is the phosphate, which differentiates the nucleotide molecule from a nucleoside molecule.
Explanation:
The answer is <span>B. In both oogenesis and spermatogenesis, the cells become haploid after meiosis I.
Gametogenesis is a process in which gametes are produced. Oogenesis is a process in which egg cells are produced and spermatogenesis is a process in which sperm cells are produced. Both processes include meiosis.
Original diploid cell (primary oocyte or spermatogonium) has 46 chromosomes. After meiosis I, there are two haploid cells. After meiosis II, there are 4 haploid cells because meiosis II is similar to mitosis. The difference between spermatogenesis and oogenesis is that those 4 cells after meiosis II in spermatogenesis are all sperm cells, and in oogenesis only one of them is egg cell.</span>
