Answer:
It only allow certain material to enter the cell
Answer:
Mechanical digestion involves physically breaking down food substances into smaller particles to more efficiently undergo chemical digestion. The role of chemical digestion is to further degrade the molecular structure of the ingested compounds by digestive enzymes into a form that is absorbable into the bloodstream.
Explanation:
Answer: B
Explanation: So air, like most other substances, expands when heated and contracts when cooled. Radiation cooling occurs when air near the ground is cooled by the Earth's surface losing heat by radiation.
The answer is 44 chickens and 28 rabbits.
We have a system of two equations.
x - the number of rabbits
y - the number of chickens
Both chicken and rabbit have only 1 head, so the first equation is: x + y = 72.
Since rabbits have 4 legs and chickens 2 legs, the second equation is: 4x + 2y = 200.
Now, let's solve the system:
x + y = 72
4x + 2y = 200
___________
y = 72 - x
⇒ 4x + 2 · (72 - x) = 200
4x + 2 · 72 - 2 · x = 200
4x + 144 - 2x = 200
2x + 144 = 200
2x = 200 - 144
2x = 56
⇒ x = 56 ÷ 2 = 28
So, there are 28 rabbits.
Since
y = 72 - x = 72 - 28 = 44,
there are 44 chickens.
