Deep black soil is more productive due to the presence of ............. .

What percentage of the total phosphorus in vertebrates is incorporated into bones and teeth (in $\%$)?

Which of the following pairs regarding soil characteristics is $INCORRECT$?

In hydroponic vegetables,the $pH$ preferred by most vegetables is slightly

Soil salinity is measured by

$A$: Chelating agents used in improving the availability of some minerals in soil are actually electron acceptors.
$R$: They increase the solubility of some minerals in acidic soils.