Add spaces: Theupperendofmarket-ProdigitalSLRseemstobeintherange21–24MP,sowhileleavingroomtomoveupwardinthelowerendofthemarket.

Answer: The upper end of market-Pro digital SLR seems to be in the range 21 – 24 MP, so while leaving room to move upward in the lower end of the market.

Add spaces: ThePolarLoopActivityTracker(optionalincl.PolarH7cheststrap)recordseveryofyourmotionsandshowsyouhowactiveyouareorremindsyou,whenyoudonotmoveenough.

Answer: The Polar Loop Activity Tracker (optional incl. Polar H7 chest strap) records every of your motions and shows you how active you are or reminds you, when you do not move enough.

Add spaces: DuringspawningseeksHowever,downto1800metersdybde.

Answer:
During spawning seeks However, down to 1800 meters dybde.