Explanation:
Karyotyping is <u>a test to examine chromosomes in a sample of cells</u>. This test can help identify genetic problems as the cause of a disorder or disease.

Answer:
The correct answer will be-
1. Observation-option B.
2. Hypothesis-option A.
3. Experiments- option C.
Explanation:
A scientific method involves various steps to explain a natural phenomenon of nature. It begins with making an observation which leads to asking the scientific question. The researcher does background research and proposes a hypothesis which could be tested through experiments. The experiments could prove or disprove the hypothesis based on the results.
In the given question the observation made is an equal amount of A and T and G and C are observed. It leads to a hypothesis which shows that this could have happened due to the winding of two strands of DNA and the experiments was performed through X-ray diffraction pattern.
Thus, the selected options are the correct answer.
Answer:
water is evaporated into the air then the water molecules get too heavy and come back down as snow/rain/ect