Brain stem is formed by .........

$\begin{array}{|l|l|} \hline Column\,\,-\,\,I & Column\,\,-\,\,II \\ \hline (a)\,\,Trygon & (i)\,\,Echinodermata \\ \hline (b)\,\,Ascidia & (ii)\,\,Viviparous \\ \hline (c)\,\,Asterias & (iii)\,\,Chondrichthyes \\ \hline (d)\,\,Kangaroo & (iv)\,\,Oviparous \\ \hline (e)\,\,Penguin & (v)\,\,Urochordata \\ \hline \end{array}$

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Which of the following diseases is caused due to helminth infection?

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In which one of the following organisms its excretory organs are correctly stated?

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Infection of Entamoeba histolytica can be checked by

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Consider the following statements

$I.$ Ladybirds and dragonflies are used to get rid of aphids and mosquitoes

$II.$ The bacteria Bacillus thuringiensis $(B t)$ are used to control butterfly caterpillars

$III.$ Trichoderma sp. free living fungi, are present in root ecosystems where they act against several plant pathogens

$IV.$ Rhizobium is a symbiotic bacterium that lives in the stem of legumes