Answer:
1. deoxyribonucleic acid, a self-replicating material which is present in nearly all living organisms as the main constituent of chromosomes. It is the carrier of genetic information.
2.the material or protoplasm within a living cell, excluding the nucleus.
3.a microscopic network of protein filaments and tubules in the cytoplasm of many living cells, giving them shape and coherence.
Explanation:
Three important characteristics such as a notochord, a dorsal hollow nerve cord, and pharyngeal gill slits, should appear at any stage of their life cycle. These are the characteristics of the chordates. Members of echinoderms share resemblance with chordates in presence of a notochord.
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Answer:
It is essentially a broth culture filtrate of the penicillium mould.
Explanation:
- Alexander Fleming invented penicillin an antibiotic in 1928. These have been rated as the most important scientific discovery, being among the first antibiotics to be effective against bacterial infection.
- Penicillin belongs to different families that are selective against a large variety of bacteria.
- In fact, this antibiotic was discovered by fleming and accident in which he left a platter containing staphylococci open and was contaminated by green mould. There was an area of inhibited bacterial growth around the mould from which he inferred that the mould produced a material that inhibited bacterial growth. This was found to be a penicillium mould through further study.
- I assume penicillin is the most significant discovery so far because it was the first antibiotic ever discovered against bacterial infection in the absence of any drug.