Answer:
1- Option A) describes an index fossil. Trilobite existed for a short time, but was abundant and lived in many locations.
2- Option B) Continents were once joined and have since drifted apart.
Explanation:
1) Fossils are animal and vegetable rests found in different strata of sedimentary rocks. Sedimentary layers deposit chronologically, so they are used to reflect history. They keep in each layer some of the forms of life that inhabited that area in the past. These fossils turn to be very useful while dating ages. The term Index fossils refer to those fossils that only existed in a given era or geological period during evolution.
Index fossils must:
• Be easily recognizable and distinguishable from all the other fossils
• Have lived in a relatively short geological period
• Present a wide geographic distribution
• Have lived in different sedimentary basins
• Appear in different types of rocks
• Be abundant
<em>A) Trilobite existed for a short time, but was abundant and lived in many locations. </em>The species accomplish the requirements. It is easily recognizable, had a wide geographic distribution, was abundant, and lived for a short time.
2) The tectonic plates theory states that there is a continual movement of the crust. It explains the movement of the different plates and their directions and interactions. The continental drift theory explains how these movements have been taking place since millions of years ago. When continents were together in a unique continent, many species used to inhabit it. When plates started to separate, they took some of these species that got apart by the ocean. Some species were already dead and fossilized, while some other organisms died during continental drift and got fossilized after the divergence. <em>The existence of the same fossils, placed in the same layers and of the same age, suggests that they used to inhabit the same area and died during the same time, meaning that continents were together when they got fossilized. </em>
Answer:
The atom, the basic building block of matter, consists of a core nucleus surrounded by negatively charged electrons. Inside the atom nucleus contains a mixture of positively charged protons, and electrically neutral neutrons. All atomic electrons bind to the nucleus through electromagnetic force. A ground of electrons bound together will form individual molecules. An atom with an equal number of protons and electrons will hold neutral. An ion has positive or negative charge, either through a lack of electrons or an electron excess. The number of protons determines the formation of chemical elements, while as the number of neutrons determines the element's isotope. Most of the atom's mass has a concentration compacted within its nucleus; however, protons and neutrons hold about the same mass. Electrons bound to atoms hold a percentage of stable energy levels, otherwise known as orbitals, which undergo transitory processes through absorbing or omitting photons with equal energy levels. Electrons determine an element's chemical properties, thus influencing an atom's magnetic properties.
Explanation:
D. All of its wavelengths are harmful
This is false, because a lot of electromagnetic radiation (such as visible light we see with our eyes) is not harmful.
<span>Ecological balance can be defined as the equilibrium or stability of species
(animals and plants) to natural conditions or environment. A decrease in the
variety or diversity of, environment or those natural conditions which may
result in an imbalance or instability of the ecological balance means a
reduction in biodiversity.</span>
Answer:
Urban sprawl is basically another word for urbanization. It refers to the migration of a population from populated towns and cities to low density residential development over more and more rural land. The end result is the spreading of a city and its suburbs over more and more rural areas.
