Biology problems in grade one of junior high school Research on the experiment of "the influence of plants on air humidity" 1. Your question () 2. The hypothesis you made () 3. After comparing the air humidity of bare land, grassland and dense shrub, you know that the maximum air humidity is () and the minimum is () 4. Through inquiry, you come to the conclusion that () 5. Please refer to the relevant information and talk about the role of plants in improving our living environment? Solving++

Put forward the question: whether plants have influence on the air humidity; make the hypothesis: plants can increase the air humidity; compare the air humidity of bare land, grassland and dense shrub, the air humidity of the largest is (dense shrub), the smallest is (bare land); through the research, the conclusion is & nbsp; (& nbsp; & nbsp; & nbsp; Planting

Take two pots of Pelargonium with the same size and vigorous growth, and do not water them for several days until the plants wither. Number them as a and B respectively. Spray water on the leaves of Pelargonium in a pot, and pour the same amount of water into the soil in B pot. Observe after one hour
(1) Changes of two plants: a pot______ B Basin_ .
(2) This experiment shows that_____________ .

(1) The Pelargonium in the second basin began to revive
(2) Water is transported up from the bottom of the pipe

A kind of operation * is defined in the range of non-zero rational numbers. The rule is: a * b = AB + A / B + 1. According to this rule, (- 3) * (- 1 / 2)

a*b=ab+a/b+1
（-3）*（-1/2）
=-3×(-1/2)+(-3)/(-1/2+1)
=3/2+(-3)/(1/2)
=3/2-6
=-9/2

There are 120 apple trees in the orchard. Peach trees are 20% less than apple trees, and apple trees are 20% more than pear trees

Peach trees: 120 * 80% = 96
Pear trees: 120 / (1 + 0.2) = 100

The square of the algebraic expression (a-b); the value of a is () a greater than zero less than zero C equal to zero D greater than or equal to zero
Tell me why

D is greater than or equal to zero

There were 300 students in sunshine primary school. The number of girls increased by 5% and that of boys increased by 4% this semester. The total number of students increased by 13. How many girls were there in sunshine primary school?

Set the original girls x boys 300 - X
x * 5% + (300-x) * 4% =13
x = 100
There are 100 girls

3 out of 4 times 99 plus 3 out of 4. It's a process. Thank you

=3/4×99+3/4×1
=3/4×(99+1)
=3/4×100
=75

The retail price of a kind of soap in a supermarket is 3 yuan per piece. In order to promote sales, the supermarket offers two preferential methods: (1) one piece is at the original price, and the rest is at the original price
20% discount; (2) 20% discount on the original price. When you buy how many pieces, are the prices of the two discount methods the same?

0.8x=1+0.7（x-1)
0.1x=0.3
x=3

FX = 9 to the power of X + 1 / 2 - 3 to the power of X + A, X belongs to 1,2, the maximum value is 5, the minimum value

A:
f(x)=9^(x+1/2)-3^x+a,1

The distance between a and B is 420 kilometers. Two cars drive from a to B at the same time. The first car travels 42 kilometers per hour, and he arrives at B
How many kilometers per hour does the second car travel?

Driving time of the first car
=（420+84）÷42
=12 hours
Second car speed
=（420-84）÷12
=28 km / h