Cytokines are the ligands (signal molecules) especially in immune system cell communication. Cytokines can be a part of all of the
cell signaling types EXCEPT?
A)
endocrine signaling
B)
autocrine signaling
C)
paracrine signaling
D)
direct signaling through gap junctions

i think it is dna, i'm not totally sure but i think it might be.

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.

to this one it would be receptive field