Index fossils are used to determine the relative ages of rock and fossils and are also used to define the boundaries between geologic periods.
<u>Option: A</u>
<u>Explanation:</u>
The fossils which are recognized as fossils guides or indicator fossils are used to classify and recognize geological or faunal periods, termed as index fossils. It must be of short vertical reach, wide geographic distribution and swift patterns in evolution. It helps to assess the rock layers ' age and helps to date other fossils found close and around them. For an instance, Ammonites were abundant in the Mesozoic period between 245 to 65 mya, they have not been found after the Cretaceous era, as they became endangered during the K-T extinction (65 mya).
<span>When reading a buret, the initial reading should be taken from the top of the glassware and the final volume should still taken at the top. If the buret is completely, the initial volume for most buret would be zero. though, there are some where their initial starts at 50 decreasing to zero.</span>
The vector B will have two components and those components will be called resultant vectors.
<h3>What is a component vector?</h3>
A component vector is a unit vector that represents a given vector in a particular direction.
A vector can be represented in x - direction and y - direction.
- x - component of the vector = Bcosθ
- y - component of the vector = Bsinθ
Thus, the vector B will have two components and those components will be called resultant vectors.
Learn more about component vectors here: brainly.com/question/13416288
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Mostly gravity voloume and sometimes what it is made of
