According to the Scientific Method, in order to make a controlled experiment you NEED to have an hypothesis.
A controlled experiment consists of a test done by a scientist in which only one or a few variables are changed while the others remain constant in order to prove or disprove a hypothesis. This hypothesis is key to said experiment because it provides the starting point from which the professional can begin the procedure, as it helps focus on the subject that one is trying to get results from. Without a clear hypothesis, the outcome of the experimentation will not be valid nor specific.
The answer is a because the altitude is greater then the length of the width
One way to fix that sentence is to switch around the two phrases used; 'My mother and father are both scientists' and 'It must have been my destiny to become interested in biology.'
It must have been my destiny to spark an interest in Biology, as my mother and father are both scientists.
That's a way to fix that sentence used in your question.
Also, 'destiny' was spelled incorrectly.
This sentence may seem run on if you don't place a conjunction between the two phrases, or if the phrases are not switched.
If the sentence is to be used with a conjunction, it may end up like this....
My mother and father are both scientists, so it must have been my destiny to become interested in biology.
Or, you may just use a period, to change the two phrases used into two separate sentences.
Like this;
My mother and father are both scientists. For that reason, it must have been my destiny to become interested in biology.
ALSO, as you can see above, I have added a few words to the last sentence. Those three words, 'For that reason', give closure to the two sentences.
Hope this helped!
Threateningly
We can tell that because the dogs are huddled together in fear, there's some sort of danger. Also the snarling suggests they are under caution or going on defense from some danger; they feel threatened.