Earth can be divided into four main systems or spheres. Which system contains Earth’s weather and forms the different climates around the world? A. Earth's inner layers of rock and metal
B. Earth's outermost later of gases
C. the parts of Earth that contain all living organisms
D. the parts of Earth that include all of Earth's water

, and

for

step-by-step explanation:

we can analyze the pattern at which the terms increase. let us denote , , , so that we can call

note the following:

the pattern: to get the next term value, we just add the next term number (e.g. 1st, 2nd, to the previous term value (term values are the given numbers in the question, 1, 3, 6, 10, 15,

from , to get to , we add

from , to get to , we add

etc.

we need to form a recursive formula, a formula that has the next term as a function of the previous term. so a possible recursive formula can be

, and for

if you need just tell me and i will come to the rescue.

step-by-step explanation: