Very sorry if this is wrong but I believe the answer is C!
Complete question:
Which of the following pairs represent homologous structures?
- Wings of grasshopper and forelimbs of flying squirrel
-
Tentacles of Hydra and arms of starfish
-
Forelimbs of a bat and forelegs of a horse
-
Wings of a bird and wings of a moth
Answer:
3. Forelimbs of a bat and forelegs of a horse
Explanation:
Homologous characters are structures with the same basic elements. Their position in the body and the relations with adjacent structures are also the same in different organisms, and they even share the same embryological development.
These structures might show variations between the organisms exhibiting them. Variations might be related to their function and to the environment in which the organism lives. The function they accomplish is not necessarily the same in all the organisms involved.
These homologous characters are present in organisms related that share a common ancestor.
For example, whales, humans, and cats all have the same bones in the same order, but they matured differently in later embryological development.
Among the options, the only possible pair that represents homologous characters is option <em>3. Forelimbs of a bat and forelegs of a horse</em>. Both structures are the anterior extremities of the animals and share the same bones, even though they might differ in the development degree. Forelimbs and forelegs have the same position and relation with other structures in the body, and embryologically, they are the same.
<h3><u>Answer;</u></h3>
C.) The number of differences in a specific DNA sequence of two species is multiplied by a known mutation rate to determine the number of years of evolution that separate the two species.
<h3><u>Explanation</u>;</h3>
- Molecular clocks are used to date origin of species. They are based on the observation that random mutations accumulate in genes at a fairly constant rate
.
- Once a mutation rate is determined it can be used to establish dates of divergence of species.
- Molecular clocks can be used in putting a series of evolutionary events into chronological order, by comparing sequences from different species to determine when they last shared a common ancestor, in effect drawing the family tree.
<span>Answer:
Respiration is a very important process that happens in all living things. It is the way in which our bodies release energy from the food we eat.
When your hand is above your head, the flow of blood is reduced. This means the
supply of glucose and oxygen to the cells is limited, they respire less, and release less
energy. Therefore, the cells get tired more quickly and ache more readily. Pupils may
also account for their results by discussing anaerobic respiration.</span>
First pic :
plants do not have cell membranes
(plants have BOTH cell membranes and cell walls)
second pic:
ATGC
(opposite strand of the DNA TACG)
third pic:
the second choice
(selectively permeable means only specific molecules could get in and go out)
fourth pic:
option 2
(cellular respiration takes sugar (or food) and makes it into ATP energy. this is what makes us have energy after we eat)
I really hope this helped :))