What are blocks of time in the geological time scale called?
a. centuries
c. years
b. eras
d. days?

Ans: The blocks of time on the geological time scale are called eras

The history of evolution of life on earth is usually depicted in terms of geological time scale. The time scale has been divided by geologists and paleontologists into blocks referred to as 'era'. The 3 eras that have been currently identified are:

Paleozoic era which is the oldest and dates back nearly 540 million years

Mesozoic era which dates back to 250 million years ago

Cenozoic era which dates back nearly 65 million years

linda: 3 ; laura: 15

step-by-step explanation:

note that linda + laura's age is 18, and that linda is 12 years younger than her sister.

let "linda" = x , "laura" = y:

x + y = 18

x = y - 12

first, plug in y - 12 for x in the first equation:

(y - 12) + y = 18

simplify.

2y - 12 = 18

isolate the variable (y). note the equal sign, what you do to one side, you do to the other. do the opposite of pemdas. first add, then divide.

2y - 12 (+12) = 18 (+12)

2y = 18 + 12

2y = 30

(2y)/2 = (30)/2

y = 30/2

y = 15

next, plug in 15 for y in the second equation (the other equation would work too).

x = y - 12

x = (15) - 12

x = 3

linda's age is 3, laura's age is 15.

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