Who has the exercises of biology in grade one! Note: good topic! Because I want to sharpen my gun!

Who has the exercises of biology in grade one! Note: good topic! Because I want to sharpen my gun!

1. The cells are very small, generally only () a, one to tens of microns B, one to tens of nanometers C, one to tens of millimeters D, one to tens of centimeters 2_____ 、_____ , and_____ Among them, the structure that controls the material entering and leaving the cell is_____ The structure related to the succession of organisms

The point representing an integer on the number axis is the integral point, and the unit length is 1cm. If you draw a line segment AB with length of 2004cm on the number axis, what is the integral point covered by ab?
Write the solution. Be more specific
Is a the starting point and B the ending point?

The point representing the integer on the number axis is the integral point, and the unit length is 1cm. If you draw a line ab of 2004cm on the number axis, the integral point covered by ab is 2004
I have done this problem, the teacher said

A suit of clothes is 320 yuan, of which the price of trousers is one third of that of the coat. How much are the coat and trousers?

Top = 320 ÷ (1 + 1 / 3) = 240 yuan
Pants = 320-240 = 80 yuan

If A3 + A2 = − AA + 1, then the value range of a is______ ．

From the result of the reduction of quadratic radical, we can know that: − a ≥ 0A + 1 ≥ 0, the solution is - 1 ≤ x ≤ 0

12m3 = () cubic decimeter

12 cubic meters = (12000) cubic decimeters

A and B start from a and B at the same time and travel in opposite directions. A travels 80 kilometers per hour, and B travels 10% of the whole journey per hour. When B reaches 58, a reaches B at 16 of the whole journey. How many kilometers are there between a and B?

The speed ratio of a and B is: (1-16): 58 = 56:58 = 4:3; therefore, the speed of B car per hour is: 80 △ 4 × 3 = 20 × 3 = 60 (km); the distance between AB and a: 60 △ 10% = 60 △ 0.1 = 600 (km); a: the distance between a and B is 600 km

How to calculate the density of PVC pipe by weight, length and thickness?

Since it is a pipe, you need to know the inner diameter or outer diameter so that you can calculate the volume. According to the volume and mass, you can calculate the density. The details are as follows:
Let R be the outer diameter, X be the thickness, l be the length and m be the weight,
Volume v = [pi * R ^ 2-pi * (R-X) ^ 2] * l
Density u = m / V, pay attention to unit in operation

{x-3 (x-1) ≤ 7,1-2 / 3-5X

（1）
(x-3)(x-1)≤7
x2-4x-4≤0
2-2√2≤x≤2+2√2
（2）
1-（2-5x）/3＜x
x＜-1/2

After a 12 cm long cylinder is cut off by 5 cm, the surface area of the cylinder is reduced by 31.4 square centimeters. How many square centimeters is the original surface area of the cylinder? I will answer this evening, but I can't do it after today~

26 π cm2
Methods: let the radius of the bottom of the cylinder be r, so 2 π R * 5 = 31.4
R = 1 cm, then the original surface area = 2 * π R ^ 2 + 2 π R * 12 = 26 π (cm ^ 2)
Note: the surface area of the cylinder is only reduced by the side area of the 5cm long cylinder, do not add two bottom surfaces

It is known that a × 100% = B / 4 / 5 = C / 4 / 5 = D / 2, and a.b.c.d is not equal to 0

B / 4 / 5 = C / 4 / 5 is this B / 4 / 5 = C / 5 / 4
A×100%=B÷4/5=C÷4/5=D÷2
A=B*5/4=C*4/5=D*1/2
D>>C> A> B