Answer:
1) Recursive definition: 
2) At the beginning of the 4th interval
Explanation:
1)
The initial population of the bacteria at time zero is

Here we are told that the reading is taken every two hours; we call this time interval "n", so

And also, after every time interval n, the number of bacteria has tripled.
This means that when n = 1,

And when n=2,

Applied recursively, we get

And substituting p0,
(1)
2)
Here we want to find at the beginning of which interval there are

bacteria.
This means that we can rewrite eq.(1) as

By simplifying,

Which means that

However, this means that the number of bacteria is 1,350,000 after 3 time intervals; therefore, at the beginning of the 4th interval.
Answer:
A+B C. Only one of the unknown substances is a catalyst, and the others are nonreactive with A, B, or C. When 10 mL of A is added to 10 mL of B the reaction takes twenty seconds. Bubbles form when the product C is created. The student prepares three test tubes, each containing both reactants A and B. She adds unknowns X, Y, and Z to test tubes 1, 2, and 3, respectively.
Answer:
'Cross experiments done by Morgan, illustrating the X-inheritance link of a mutation Thomas Hunt Morgan moved intensely in a program of breeding and crossing miles of fruit flies at New York University in a room that was renamed the Fourth of the Flies. He tried to mutate the flies with various means (X-rays, centrifuges, etc.) .The fruit fly which has 4 pairs of chromosomes. One of those pairs was identified as containing X and Y sex chromosomes. He applied Mendelian principles in flies. Morgan's inheritance study demonstrated inheritance linked to sex, and is one of the first evidences that confirm the chromosomal theory of cross-based inheritance. In 1909, Morgan detected a fruit fly (Drosophila melanogaster) with a strange mutation which he called "white eyes", due to the coloration of his eyes (contrary to normal, which is red). Analyzing this fly under the microscope Morgan discovered that it was a male, and could use it as a stallion so that he could observe how the new characteristic of white eyes would pass from generation to generation.All the offspring of this cross will have red eyes, which He made Morgan suspect that something strange had happened, since the color of the father's eyes could not have disappeared. He decided to take a couple of "daughters flies" and cross them together, just to see what happened. Morgan's surprise was very great, observing that among the "granddaughters" flies only males had white eyes. The problem then was to explain what had happened during the hereditary transmission for the color of the white eyes only the males possessed. .
Hope it will help you ...............
Answer:
Hey there.
<em><u>There are three types of scientific investigations: descriptive, comparative, and experimental scenitific investigations.
</u></em>
<em><u></u></em>
fist we have <em><u>Descriptive</u></em> scientific investigations.
Descriptive investigations use careful observations and measurements to develop findings.
Then we have <em><u>
comparative </u></em>Investigation.
comparative investigations Involve collecting data on different populations/organisms, under different conditions (Times of year, locations), to make a comparison. for Example, Using a hand lens to examine the color and texture of four different rocks.
Lastly we have <em><u>experimental</u></em> scientific investigations.
Experimental investigations involve a process in which a "fair test" is designed and variables are actively manipulated, controlled,
I hope it helped!!!
<em>Wbob1314</em>