Answer:
your answer would be C.Streak is tested by scraping a mineral across a streak plate.
Explanation:
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All large radioactive atoms decay into smaller atoms by emitting alpha particles which consists of two protons and two neutrons. An alpha particle can also be thought of as the nucleus of a helium atom and as such they are sometimes referred to as He2+ . The positive charge is due to the lack of two electrons.
Answer:
c. selective toxicity takes advantage of structural and/or metabolic differences between host and pathogen
Explanation:
Selective toxicity is the mechanism by which antibiotics work. They cause damage to the pathogen but do not harm the host. Hence, they are selectively toxic in their mechanism. They can target both the structural or the metabolic differences between host and pathogen. Many antibiotics target unique sites in the pathogen's structure or the sites which might be present in host cells too but are not essential for the survival of the host. An example of structural difference being targeted by antibiotics is the enzymes which synthesis the bacterial cell wall so that the cell wall is disrupted. A metabolic difference being targeted would be the mechanism by which bacteria replicates so that host cell replication process is not hindered.
Answer:
The radially symmetrical deuterostome invertebrate most closely related to chordates is the echinoderm.
Explanation:
Options for this question are:
- <em>Annelid.</em>
- <em>Echinoderm.</em>
- <em>Arthropod.</em>
- <em>Mollusk.</em>
Echinoderms, like the starfish, are a phylum of organisms derived from deusterotomates, in whose embryonic development the anus is formed first, and characterized by their pentaradial symmetry and the existence of an internal skeleton. Deuterostomy establishes a link between the echinoderms and the chordates, and the possibility that they are both descended from a common ancestor.
The relationship between invertebrates, such as echinoderms, and vertebrate organisms has been studied, establishing that hemicordates are the link that links both types of organisms.
