Answer:
d. low earth orbit (LEO)
Explanation:
This type of satellites form a constellation deployed as a series of “necklaces” in such a way that at any time, at least one satellite is visible by a receiver antenna, compensating the movement due to the earth rotation.
Opposite to that, a geostationary satellite is at an altitude that makes it like a fixed point over the Earth´s equator, rotating synchronously with the Earth, so it is always visible in a given area.
Answer:
Option ‘a’ is the cheapest for this house.
Explanation:
Cheapest method of heating must have least cost per kj of energy. So, convert all the energy in the same unit (say kj) and take select the cheapest method to heat the house.
Given:
Three methods are given to heat a particular house are as follows:
Method (a)
Through Gas, this gives energy of amount $1.33/therm.
Method (b)
Through electric resistance, this gives energy of amount $0.12/KWh.
Method (c)
Through oil, this gives energy of amount $2.30/gallon.
Calculation:
Step1
Change therm to kj in method ‘a’ as follows:

$/kj.
Step2
Change kWh to kj in method ‘b’ as follows:

$/kj.
Step3
Change kWh to kj in method ‘c’ as follows:

$/kj.
Thus, the method ‘a’ has least cost as compare to method b and c.
So, option ‘a’ is the cheapest for this house.
Com·ma
/ˈkämə/
NOUN
1. a punctuation mark (,) indicating a pause between parts of a sentence. It is also used to separate items in a list and to mark the place of thousands in a large numeral.
2. a minute interval or difference of pitch.