Answer:
i want to say 6 but I am not sure
Answer: different organisms have different chromosome numbers
Explanation: eukaryote cells have more than one chromosome
chromosomes are present in most cells all the time (not in erythrocytes), but cannot be visualised except during telophase of mitosis or meisosis
bacterial cells don’t have a nucleus
The organs are known as Vestigial organs. The evolution from land-dwelling animal to the marine animals has led whales as well as dolphins, to lose hind limbs. The pelvic and leg bone serves no purpose in them and just provide the anchorage to muscles
Wild boars were brought to the United States by humans.Wild boars have quickly spread through the United States.Wild boars have established successfully in areas with warm climates.<span>Wild boars have a high reproductive rate and no natural predators. the answer is (c)
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Answer:
Watson and Crick proposed the double helical model of DNA.
Explanation:
- This model says that DNA exist as double helix. It has two polynucelotide strands running in opposite direction i.e the strands are anti-parallel.
- Each polynucleotide strand is made up of several nucleotide liknked together by phophodiester bonds.
- The two strands are not coiled upon each other but the double strand is coiled upon itself around a common axis like the spiral stair case. Here base pairs forms the stairs and backbone of two strands form railing. Back bone contains sugar and phosphate.
- The base pairing is specific, adenine always pairs with thymine and guanine always pairs with cytosine. Thus if we see any base pair, it consists of one purine and one pyrimidine.
- The two strands of DNA thus show complementary base pairing.
- The strands are held together because of hydrogen bonding between the bases in opposite strand.
- One full helical turn involves ten base pairs and the base pairs are stacked 3.4 A apart.
- This form is called as B-form of DNA.
