What atomspheric gas is used by marine organisms to make their shells

Ascientist discovers a new body between the orbit of neptune and the kuiper belt. the object is round and travels in an orbit around neptune with other space objects. the scientist claims that she has found a new dwarf planet. where is the scientist’s error?

As the pea seeds respire, the level of coloured liquid in the left hand part of the capillary tube rises. by referring to what is happening in the apparatus, explain why the level of liquid changes

Which type of stimulus do mechanoreceptors detect? sound pain heat light