Answer:
The earth’s crust is broken into separate pieces called tectonic plates (Fig. 7.14). Recall that the crust is the solid, rocky, outer shell of the planet. It is composed of two distinctly different types of material: the less-dense continental crust and the more-dense oceanic crust. Both types of crust rest atop solid, upper mantle material. The upper mantle, in turn, floats on a denser layer of lower mantle that is much like thick molten tar.
Each tectonic plate is free-floating and can move independently. Earthquakes and volcanoes are the direct result of the movement of tectonic plates at fault lines. The term fault is used to describe the boundary between tectonic plates. Most of the earthquakes and volcanoes around the Pacific ocean basin—a pattern known as the “ring of fire”—are due to the movement of tectonic plates in this region. Other observable results of short-term plate movement include the gradual widening of the Great Rift lakes in eastern Africa and the rising of the Himalayan Mountain range. The motion of plates can be described in four general patterns:
<p><strong>Fig 7.15.</strong> Diagram of the motion of plates</p>
Collision: when two continental plates are shoved together
Subduction: when one plate plunges beneath another (Fig. 7.15)
Spreading: when two plates are pushed apart (Fig. 7.15)
Transform faulting: when two plates slide past each othe
Explanation:
Answer:
Alexander Fleming
Explanation:
Which scientist developed the idea that microorganisms can cause diseases?
Paul Ehrlich
Answer:
1. 80 chromosomes are found in each of the daughter cells. 2. Two daughter cells are produced. 3. The daughter cells are identical to each other.
Explanation:
Mitosis is simply a process of cell division whereby two daughter cells that are genetically identical are produced from a single parent cell. A cell having 80 chromosomes would undergo Mitosis through these various stages:
Interphase: This can be referred to as the rest phase between cell division when mature enough for reproduction. This is a preparatory stage where DNA is duplicated and ready for the division of chromosomes
Prophase: This stage marks the beginning mitosis of the cell with 80 chromosomes. The chromatin threads start a coiling process in which the chromosomes become condensed to enable easy distribution to daughter cells without tangling.
Prometaphase: This phase commences toward the end of the prophase, where the nuclear envelop breaks down. The chromosomes move toward to the center of the cell.
Metaphase: At this stage, the duplicated chromosomes line up on the mid plane or equator of the cell. During this stage, each chromatid is condensed completely and appears thick and distinct.
Anaphase: At this stage, the chromosomes move toward the poles as each replicated copies of the DNA of the cell ends up on either side of the cell. What we would have here at this stage is an entirely two new sister chromatid having 80 chromosomes. Cytokinesis begins towards the end of this stage as the parent cell cytoplasm divides which also continues at telophase.
Telophase: This is the final phase of Mitosis where two separate nuclei are formed and Cytokinesis takes place to complete the division of the cell to form two daughter cells having the same number of chromosomes. These cells are genetically identical to the original parent cell.
