Im in
which adaptation an animal get energy?

a) birds migrating south for the winter

b) a polar bear's thick fur

c) a monkey's long tail

d) a giraffe's long neck

D) A giraffe's long tail

Explanation:

I'm guessing this is the right choice because:

a.  Migration is a survival instinct and doesn't particularly help with energy.

b. A polar bear's thick fur is to protect it from the cold and helps to warm the animal, but it doesn't supply energy.

c. A monkey's long tail is indeed useful for hanging from branch and climbing, yet they have four other limbs that aid in the same process and again, it doesn't neccessarily supply energy.

d. A giraffe's long neck is used to eat from trees since giraffes are herbivores and eat from tall trees, which counts as energy. This is because when the eaten it is later converted into protein to be used energy.

I hope this helps!

part 1: the half-life of the element is 22 years.

part 2: it will take 132.02 year for the sample to decay from 308.0 g to 4.8125 g.

explanation:

part 1: there are two ways to determine the half life time.

first way: the half life time can be determined directly from its definition as it is the time required for the sample to decay to its half concentration.

from the data the initial concentration was 45.0 g and decayed to its half value (22.5 g) in 22.0 years.

second way: the radio active decay is considered first order reaction so we can use the laws of first order reactions.

k = (1/t) ln (a/a-x), where k is the rate constant of the reaction,

t is the time of the reaction

a is the initial concentration of the reactant

a-x is the remaining concentration at time (t)

a = 45.0 g the initial concentration at t = 0 year.

at t = 22 year, a-x = 22.5 g

then k = (1/22 year) ln (45.0 g/ 22.5 g) = 0.0315 year-1.

the half-life time (t1/2) = ln 2/ k = 0.693/ k =0.693/ 0.0315 = 22 years.

part 2:

using the same law k = (1/t) ln (a/a-x),

using the given data; a = 308.0 g and a-x = 4.8125 g and the calculated k from the part 1 (k = 0.0315 year-1)

t = (1/k) ln (a/a-x) = (1/0.0315) ln (308.0/ 4.8125) = 132.02 years