Answer:
It's the 3rd option
Explanation:
Wind is caused by the differences in air pressure on Earth's surface.
The idea that "students ' immune systems have declined due to the use of hand sanitizers " is a hypothesis.
The term hypothesis refers to an intelligent guess or idea often based which is subject to scientific investigation via experiments.
A hypothesis may be right or wrong. We can only prove a hypothesis by subjecting it to a series of rigorous experiments.
Thus Collette's idea is a hypothesis.
Learn more: brainly.com/question/18284466
Answer:

Explanation:
A simple pendulum is a system consisting of a mass attached to a string, and oscillating in a periodic motion, back and forth, along an equilibrium position.
The period of a pendulum is the time it takes for the pendulum to complete one oscillation.
The period of a pendulum is given by the equation

where
L is the length of the pendulum
g is the acceleration due to gravity
From the formula, we see that the period of a pendulum does not depend on the mass.
Therefore, the only 2 factors affecting the period of a pendulum are:
- The length of the pendulum: the longer it is, the longer the period of oscillation
- The acceleration due to gravity: the greater it is, the shorter the period of the pendulum