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.
Those proteins are called apolipoprotien.
Explanation:
Dinosaurs are living organisms that depends on the environment for survival. As the asteroid hits the Yucatan Peninsula area about 66 million years a couple of things can happen:
Frictional heating of the surface as the earth collided with the asteroid. This heating will cause surface temperature to rise globally and can induce the phenomenon of global warming. This can lead to release of water from reservoirs on the earth surface and hence flooding.
The impact can lead to increase in surface pressure beyond normal and that which life has adjusted to.
Debris in form of dust will be released into the atmosphere and a global air pollution will occur. Gases useful for life will be highly polluted by the vast amount of dusts and other particles discharged into the atmosphere.
Nutrients enter a cell up the concentration gradient by the process of active transport.
Chemical energy is stored in the battery cells and converted to electrical energy when it's needed by the toy robot