Me with questionsanswer both questions at the same not only one.. 19 points how would the pattern of apoptosis differ in a duck's webbed foot compared to the pattern of apoptosis in a mouse's foot? what are cyclins? what do cyclins do?

1. a mouse's toes undergo apoptosis during a late stage of development. due to signaling protein: BMP4 that instructs cells in webbing to undergo apoptosis

- both embryos express BMP4 gene but differ in expression of gene Gremlin- ducks

-- Gremlin protein inhibits BMP4 from signaling for apoptosis= webbed foot

2. Cyclin is a family of proteins that control the progression of cells through the cell cycle by activating cyclin-dependent kinase

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.