Answer: The human body is organized at different levels, starting with the cell. Cells are organized into tissues, and tissues form organs. Organs are organized into organ systems such as the skeletal and muscular systems
Explanation:
Answer:
Option (2).
Explanation:
Zygote is formed by the fusion of the male and female gamete during the process of sexual reproduction. The zygote undergoes further development inside the female womb.
The embryonic period starts from the third week after the conception. The important organs and structure development occur during the embryonic period. The formation of three germ layers occur in this period.
Thus, the correct answer is option (2)
<u>Answer</u>: option B they have a random gene mutation that affects their fur colour.
<u>Explanation</u> :-
- <em>Variation</em> is the phenomena which occurs in all populations.
- These variations result in slight differences in the phenotypes of individuals .
- These variations only arise due to <em>random mutations </em>that arise in the individuals’ genome and then can be inherited by their offspring.
- There is always a probability of one particular trait to make the individuals survive better in the environment as compared to other trait.
- The individuals having the trait that helps them to survive better in the environment tend to survive more and leave more progeny. This is termed as <em>survival of the fittest</em>.
- Thus, according to the question it can be inferred that the dark fur colour arose due to a <em>random mutation </em>since it is the only source of variation. Since, in the given environmental conditions the mice having the dark fur colour were less susceptible to the predators they are better fitted to survive.
- The dark brown fur coat mice, survive better, leave more progeny and hence, increase their population with time. However, the orginal source of origin of this trait was a random mutation. Had this mutation not occured, the dark coloured fur mice would not have been there.
So, a <em>random gene mutation affecting the fur colour made the dark coloured mice first appear in the population.</em>
