The correct answer is A.
Animal cells do not have a cell wall.
A cell wall is the rigid, outermost covering of plant cells and is made up of cellulose. It is absent in animal cells. The cell wall is visible under a light microscope.
Animal cells are instead covered by a cell membrane. It is made up of lipids, proteins, and small amounts carbohydrates. It is a thin and delicate structure that can only be seen using an electron microscope.
A population decrease in primary producers would affect the ecosystem negatively because everyone who ate the primary consumers would have a lack of food.
Answer:
(a) number of strands (n) = time (t) ÷ proportionality constant (k)
(b) The time needed for the bacterial to double its initial size is 3.36 hours.
Explanation:
(a) Let the rate (time) be represented by t and the amount (number) of strands of bacteria be represented by n
t is proportional to n, therefore, t = kn (k is the proportionality constant)
Since t = kn, then, n = t/k
(b) Initial amount of strands = 300
Amount of strands after 2 hours = 300 + (300 × 20/100) = 300 + 60 = 360
k = t/n = 2/360 = 0.0056 hour/strand
Double of the initial size is 600 (300×2 = 600)
Time (t) needed for the bacterial to double its initial size = kn = 0.0056×600 = 3.36 hours
It has a dorsal nerve chord
