which 4 things are needed for life on any planet?

Answer 1

Not sure if you mean for life to develop on a planet or for a planet to be able to be colonised?

A habitable zone includes

(a) Sufficient gravity to retain a breathable atmosphere or one that can be terraformed to be breathable

(b) A temperature range at which water exists principally in a liquid form (not steam or ice) and life-forms can be comfortable at both extremes of the temperature range (which probably implies a nearly circular orbit around a star that is not highly variable in luminosity),

(c) protection from harmful radiation e.g. an ozone layer (but also distance from a source of such radiation: e.g. not too close to a supermassive black hole at the galactic centre or a pulsar)

(d) a Population I star which is "metal-rich" so that a rocky terrestrial planet can develop and organic chemicals based on carbon (possibly sjlicon) can develop on it which will form the basis of living cells.

(e) the capacity to grow food (not necessarily in soil: hydroponocs may be possible) and to become self-sufficient in agriculture

(f) the raw materials from which shelter, power sources and transport can be made.

(g) freedom from comet and asteroid impact and volcanic and seismic activity.

(h) renewable sustainable energy sources (e.g. water wave or wind power) and the means to harness them.

Answer 2

Life, now there's a question:
1. Water (this is paramount)
2. Reproduction
3. Heat
4. Food

Answer 3

form of brething, food, water, and shelter.... friendship, love and faith, would be good also but you only said 4.... and you would die without the first ones.

Answer 4

Air, water, food, shelter.

Answer 5

Actually its two, the right environment and reproduction.