Answer:
Because photosynthesis is a source of oxygen, it seems intuitive that photosynthesis evolved first: once enough O2 was in the air, then respiration would be able to arise in the newly oxygen-enriched atmosphere. However, some biologists have argued since the 1970's that respiration in fact evolved first.
Answer:
D. N
Explanation:
Meiosis is a kind of cell division which produces daughter cells that are genetically different from the parent cell and have a reduced number of chromosomes (by half).
Meiosis occurs only in reproductive cells to produce gametes. If a diploid (2n) cell undergoes meiosis, a haploid (n) daughter cell will result. This means that the chromosome number has been reduced by half in order to maintain the chromosomal number of the next generation.
Answer:
Long beaks of medium ground finches allows them to opt for alternate sources of food in times of extremities while this is not the case with the cactus finches.
Explanation:
The medium ground finches have larger beaks and thus apart from small seeds they can also break open the large seed. In case if the small seeds get scarce, a medium ground finch can still survive by taking advantage of feeding on alternate source of food but small beaked birds such as cactus finches shall die out of starvation.
This adaptation of medium ground finches gives it a survival advantage over the cactus finches
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Answer:</u></h2>
<u>cardic muscles:</u> are present only in the heart .single cell is not very strong by itself, millions of cardiac muscle cells working together are easily able to pump all of the blood in the body through the heart in less than a minute. Cardiac muscle cells have a branched shape so that each cell is in contact with three of four other cardiac muscle cells.
<u>characteristics of cardic muscles: </u> one nucleus ,striated, involuntary, branched and joined to one another by intercalated discs that contain gap junctions for depolarization between cells and hold the fibers together when the heart contracts.
First comes fertilization, when two gametes combine to form a zygote.
