How do emission and reflection nebulae differ? (1 point) the presence of young stars
contain remnants of stars
hard tine edges
interactions with light

An emission nebula is a cloud of ionized gas. The most common source for ionizations are high energy photons emitted from a nearby star. These can be among some of the most colorful objects in the sky. Reflection Nebulae are clouds of dust which are simply reflecting the light of a nearby star or stars.

Explanation:

interactions with light

Explanation:

enzyme speed up the reactions

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.