Homeostasis is the body's ability to maintain constant conditions when conditions change.
a. internal; external
b. external; internal
c. oxygen; temperature
d. temperature; ph

The  best answer is a - internal : external
Homeostasis is the body's ability to maintain constant internal conditions when external conditions change.

It is the ability of an organism or  a cell to regulate its internal conditions, usually through a system of feedback controls so as to stabilize the health and functioning regardless of the outside changing of conditions..

For example in man, homeostasis occurs when the body regulates body temperature  in an effort to maintain an internal temperature at around 37° C. 

i would have a lunch. it's one big package of food, making it one food. : p

a

explanation:

many plants naturally reproduce this way, but it can also be induced artificially. horticulturalists have developed asexual propagation techniques that use vegetative plant parts to replicate plants. success rates and difficulty of propagation vary greatly. monocotyledons typically lack a vascular cambium and therefore are harder to propagate.