(1) What proteins bind to foreign invaders and mark them for destruction

(2) What catalyze chemical reactions

Antibodies are proteins that bind to foreign invaders and mark them for destruction by phagocytic cells in a process known as opsonization.

Enzymes catalyze chemical reactions by lowering activation energy barriers and converting substrate molecules to products.

answer: - few nutrients

high pressure

low temperatures

explanation: 1. few nutrients:   open-ocean zone is located way far from the land, which is the main source of the essential nutrients.2. high pressure: pressure increases by 1 atmosphere for every 10 meters increase in depth.3. ample sunlight: a large fraction of the sunlight is reflected back to the atmosphere from the sea surface. 4. varying salinity: below the thermocline, the water is isolated from the atmosphere so the salinity remains stable over the year.5. low temperatures:   the temperature of open-ocean zone ranges from a low of -2°c to an average of 17°c

he is very short, and he can only reach halfway up on the elevator buttons. but on a rainy day, he has his umbrella with him, and he uses it to poke the button at the top.