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>
For most prokaryotes, they do not contain a nucleus.
The correct answers would be :
A) cell membrane
C) cytoplasm
D) DNA
E) ribosomes
For making bones I think it's Magnesium
Answer:
ecological dominants
Explanation:
In an ecosystem, organisms of same and different species are usually found. However, some organisms appear too commonly than others in that particular ecosystem. These commonly observed organisms (plants and animals) due to their large numbers are called DOMINANT species. An ecological dominant species is that which numerically outshines its competitors in an ecosystem.
A species may be dominant because it is better adapted to certain processes than Its competitors e.g. getting resources, disease resistance etc. or even deters its competitors. Hence, they appear large in number. This is the case of the abundance of pinyon pine and juniper trees along the desert slope of the sierra nevada mountains in california. In that ecosystem, these two plants dominate, hence, will be referred to as ecological dominants.
