The weight of an object can change because of the forces acting on the object. Which force causes the weight of an object to change?

In "the man in the water," what was the remarkable occurrence that rosenblatt reported?

Biology ! the conversion of inorganic carbon to organic carbon by plants during photosynthesis is known as _[blank]_. filtration immigration reabsorption primary production

Several billion years ago which gas was the least prevailant in the atmosphere