Sand is a granular material composed of finely divided rockand mineral particles. It is defined by size, being finer than gravel and coarser than silt. Sand can also refer to a textural class of soil or soil type; i.e., a soil containing more than 85 percent sand-sized particles by mass.[1]
The composition of sand varies, depending on the local rock sources and conditions, but the most common constituent of sand in inland continental settings and non-tropical coastalsettings is silica (silicon dioxide, or SiO2), usually in the form of quartz. The second most common type of sand is calcium carbonate, for example, aragonite, which has mostly been created, over the past half billion years, by various forms of life, like coral and shellfish. For example, it is the primary form of sand apparent in areas where reefs have dominated the ecosystem for millions of years like the Caribbean.
Sand is a non-renewable resource over human timescales, and sand suitable for making concrete is in high demand.[2] Desert sand, although plentiful, is not suitable for concrete, and 50 billion tons of beach sand and fossil sand is needed each year for construction.
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They put a camera up to the microscope! I’ve done that with my phone camera and it’s so cool!
Answer:E is as far from C as it is from D. So,CE = E-C = (-1-5,0-2) = (-6,-2)So, add that much to E and you getD = E+(E-C) = (-1,0)+(-6,-2) = (-7,-2)
Explanation:
A.The genotype frequencies can be determined by dividing the number of individuals with a genotype by the total number all the individuals.
FF genotype frequency:
98÷200=0,49. There are approximately 5 <span>homozygous dominant mice in 10.
Ff genotype frequency:
84</span>÷200=0,42. There are approximately 4 <span>heterozygous mice in 10.
ff genotype frequency:
18</span>÷200=0,09. There are approximately 1 <span>homozygous recessive mouse in 10.
B.To determine the frequency of an allele we can divide the number of times that the allele appears by the total number of alleles.
F allele frequency:
</span>
<span>=0.7
There are 7 F alleles in 10 random alleles.
f </span>allele frequency:
=0.3
There are 3 f alleles in 10 random alleles.<span>
</span>
The right answer is <span>Refractory period.
At the moment when the action potential is emitted, the fiber being depolarized, it is impossible to depolarize it again. It is, therefore, necessary to wait until the membrane potential returns to a value below the critical threshold in order to be able to excite it again. We are thus led to distinguish two periods that characterize its excitability.
An absolute refractory period: during which any stimulation, even supraliminal, is ineffective since the fiber is already depolarized.
A relative refractory period: during which a second action potential can be omitted provided that the depolarization produced by the excitation reaches the critical threshold, which implies that it is more important since the value of the resting potential has not been restored yet.</span>