MCQ
Life originated in:
- APrecambrian era
- BProterozoic era
- CMesozoic era
- DCenozoic era
Explanation:
Precambrian is one of the four eras in earth's geological history.
Precambrian actually meant period before the Cambrian period of the Palaeozoic era.
Precambrian is divided into three periods- Azoic (no life), Archaeozoic (invisible life) and Proterozoic (age of early life).
It is believed that life appeared in Archeozoic period of Precambrian era.
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| Column $I$ | Column $II$ |
| $(a)\; XX-XO$ method of sex determination | $(i)$ Turner's syndrome |
| $(b)\; XX-XY$ method of sex determination | $(ii)$ Female heterogametic |
| $(c)$ Karyotype$-45 $ | $(iii)$ Grasshopper |
| $(d)\; ZW-ZZ$ method of sex determination | $(iv)$ Female homogametic |
Select the correct option from the following
$I.$ 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
Which of the statements given above are correct?