Answer:
B
Explanation:
B: Differential survival and reproduction
change enviroment causes natural selection
<span>D. they take hundreds to thousands o years to complete a cycle</span>
Answer: For three traits inherited in a dominant/recessive pattern, the probability of an offspring in a trihybrid cross between parents heterozygous for all three traits to be recessive at exactly two of the three loci is 23/64.
Explanation: Let A, B and C represent the dominant alleles and a, b and c represent the recessive alleles. The genotype of each of the parent will be AaBbCc since it has been said to be heterozygous for all the three traits. There are eight (8) possible different types of gametes from each of the genotype. This can be calculated using 2^n where n is the number of heterozygous loci.
The number of heterozygous loci in the genotype AaBbCc is three (3). 2^3 = 8. The gametes are;
ABC
ABc
AbC
Abc
aBC
aBc
abC and
abc.
Therefore, sixty-four possible offsprings are expected from the cross AaBbCc x AaBbCc.
Out of these offsprings, twenty-three (23) are expected to be heterozygous at two loci as boldly shown in the attached image.
Answer:
True
Explanation:
Reproduction is one of the essential characteristics of all living beings. However, if they reproduce to their full capability, the number of offspring would be higher than the available resource. Due to this reason there is always shortage of resources and hence competition arises among the species.
The fit species survive among all the competing species while the remaining weak species die. As Darwin also said that species have the ability to reproduce uncontrollably therefore, competition among the species for survival is a mode of population regulation
Hence, the given statement is true
Viruses are not considered "alive" because they lack many of the properties that scientists associate with living organisms. Primarily, they lack the ability to reproduce without the aid of a host cell, and don't use the typical cell- division approach to replication.