A) a piece of wood b) sunglass lenses c) a piece of paper d) a clear glass vase which of these is an opaque object?

An opaque object is any object that is not transparent (allowing all light to pass through it), or translucent (allowing some light to pass through it.) Knowing this we can auto-matically dismiss option D),B), and C) because these all let some form of light through them  so our answer would then be A) because light does not pass through wood like it would the others.

answer by yourhope:

hi! : )

in which structure in the nucleus are ribosomes made?

b) nucleolus!

: )

estuaries are the partially enclosed coastal bodies of brackish water formed at the mouth of sea where river meets an ocean. it is a transition zone between river and sea water so estuaries are influenced to both marine environment such as tides, waves and to riverine such as flow of fresh water and sediments. the mixing of sea and fresh water provide high level of nutrients, making estuaries a high product habitats.

many estuaries suffers degradation from a variety of human activities like erosion from deforestation, overgrazing, overfishing, drainage and eutrophication.

so from the above statement answers will be

1. false as estuaries are formed due to both brackish and freshwater.

2.true, due to high productivity estuaries are breeding ground for many marine species.

3. direct and indirect activities of man that contribute to pollution and deposition of sediments.