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Explanation:
Invading infectious diseases can, in theory, lead to the extinction of host populations, particularly if reservoir species are present or if disease transmission is frequency-dependent.
Answer:
Ss and ss
Explanation:
<em>Since the smooth trait (S) is dominant over the wrinkle trait (s), the genotype of the wrinkled pea parent is definitely </em><em>ss</em><em>.</em>
<em>Also, some of the progeny had wrinkled pea texture (ss). Each of the 2 wrinkled alleles must have been donated by each of the parent. It thus means that the smooth pea parent is heterozygous for the trait (</em><em>Ss</em><em>).</em>
Now, let us look at a cross between the two parents;
Ss x ss
Progeny: Ss, Ss, ss, ss.
Phenotypically, 50% of the progeny are smooth peas while 50% are wrinkled.
Looking at the population of each of the phenotype resulting from the cross. 252:247 is approximately a 50:50 ratio.
Hence, the genotypes of the two parents are Ss and ss.
Normal polarity
Explanation:
Earth's magnetic field used to be twice as strong 1.5 billion years ago as it is today and Earth's temperature other than what the geologists see from the 'normal' pattern. It has been noticed that some volcanic rocks were magnetized in opposite direction to the direction of the local Earth's field. It is clear that the Earth has experienced the normal polarity 1.5 years ago but at that time, the Earth's polarity was poorly understood.
