B. sent through the atmosphere
Answer:
option D
Explanation:
Sunspots are the spot that appears on the sun, this spot appears darker than the surrounding surface of the sun.
Sun magnetic field goes through a cycle and this cycle is called the Sunspot cycle. Every 11 years the magnetic field of the sun completely flips. This sunspot cycle affects activity on the surface of the sun.
Sunspot cycle is the pattern of solar activity where an average number of sunspot gradually increase and decrease.
Hence, the correct answer is option D
The new period will be 2.486 days.
<h3>What is the period?</h3>
The period is found as the ratio of the angular displacement and the angular velocity. Its unit is the second and is denoted by t. The value of time needed to complete the rotation is the total period.
Given data;
Mass of a star,m= 1.210×10³¹ kg
The time period for one rotation of the star, T = 20.30 days
D' = 0.350 D
R' = 0.350 R
From the law of conservation of angular momentum;

Hence, the new period will be 2.486 days.
To learn more about the period, refer to the link;
brainly.com/question/569003
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B. Greenhouse technology
Since the green house will help keep the pest and harmful conditions. The greenhouse will be able to control temperatures and will keep out harmful bugs. You/I will be able to provide the tree with the perfect sequence of growth.
Answer with Explanation:
We are given that
Diameter=0.030 m
Length of sprue=
=0.200 m
Metal volume flow rate,Q=0.03
Q=
because 1 minute=60 seconds
Let 1 for the top and 2 for the bottom






Pressure at the top and bottom of the sprue is atmospheric

Substitute the values






Reynolds number=


Substitute the values then we get
Reynolds number=
Reynolds number=42525
The Reynolds number is greater than 4000 .Therefore, the flow is turbulent.