The demographic transition is a process of change that ultimately leads to a low total fertility rate and a high crude death rate.
zero population growth and a high crude death rate.
a low rate of natural increase and a declining population.
a low rate of natural increase and a larger total population.
zero population growth and an increasing total fertility rate.

The scientist can conclude that there is a decrease in the natural resources due to human activities. because of innovation and modernization of the environment, then there goes pollution and other bad effects that destroys the natural resources.

Sonar is an application of the doppler effect used by submarines.  this test was on k12.

Answerbeaches;

In a right-angled triangle: 1- the hypotenuse is the longest side2- we can apply pythagorean rule which states that: (hypotenuse)^2 = (side1)^2 + (side2)^2for the given triangle,longest side is 15 cm  side1 = 9 cmside2 is 12 cm  to check whether the triangle is right-angled or not,compare (15)^2 to the summation of (9)^2 and (12)^in other words, compare 225 to the summation of 81 and 144if they are both equal, then the triangle is right-angles, otherwise, it is not.you haven't provided the diagram showing her work, so i cannot tell the choice. however, apply my explanation to the question you have.