I believe the answer is <span>D. Examining the different layers of heart tissue</span>
The Mesozoic Era<span> began 252.2 million years ago, following the conclusion of the </span>Paleozoic Era<span>, and ended 66 million years ago, at the dawn of the </span>Cenozoic Era<span>.</span>
Answer:
The correct answer is B. Worms move through changes in body structure caused by contraction of muscles compressing their watery fluid.
Explanation:
The hydroskeleton consists of a fluid-filled cavity, surrounded by muscles. The fluid pressure and the action of the muscles that border it, serve to change the body's shape and produce a movement such as digging or swimming. The successive contraction of various metamers, which are provided with bundles of circular and longitudinal muscle fibers, stretching and thickening parts of the body, allow it to move horizontally. Hydrostatic skeletons have a role in the locomotion of annelids, nematodes and other invertebrates. The hydroskeleton has similarities with the hydrostatic muscles.
Griffith experiment
Griffith used two types of bacteria in his experiment
1. R-type: it was non-virulent and cause no disease in mice
2. S-type: It was virulent and cause disease in mice which lead to death.
However when heat killed S-type was applied no disease was occurred in mice. Then he mixed heat killed S-type and live R-type and injected it into mice. He was expecting that no disease will be caused in mice.
Results
However, mice was died.
Conclusion
He was confused from this experiment. But later it was confirmed by other scientists that DNA from heat killed S-type was shifted to R-type. the progeny which formed from this transfer of DNA were virulent and cause the death of mice.
significance
It was concluded from this experiment that DNA is a hereditary material which transfer characters from parents to offspring.
