Kidney stones are mainly formed by which of the following compound ?
[a] sodium chloride[b] silicates[c] calcium bicarbonate[d] calcium oxalate

Which system revise and send electrical signals throughout the body

Hurry which of these is true about index fossils? a) are very scarcely found b) used as guides in relative dating c) found in the youngest layer of the rock d) used as reference points in absolute dating

Lucia is walking barefoot in her yard. she accidentally steps on a nail. how will her nervous system work to generate a reaction? arrange the eventschronologically.