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Tema [17]
3 years ago
14

1. How many periods are there in the periodic table? *

Biology
1 answer:
jok3333 [9.3K]3 years ago
3 0
The periodic Table has 7 periods and 18 groups. The number of valence electrons in an atom of sulfur is 6, calcium has 2, chlorine has 7 and arsenic has 5. The element that corresponds to the atomic number 10 is Neon, for 18 it is argon, for 36 it is krypton, and for 90 it is thorium. Na and CI belong to the same period, as does H and He. An element found in period 4 would have 4 energy levels. The transition elements are in groups 3-12. Strontium would be more chemically similar to calcium, because they are both in the same family/group. The heaviest noble gas is radon. The heaviest alkaline earth metal is radium.
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Rivers and streams are biodiverse ecosystems that are sensitive to change. please select the best answer from the choices provid
mylen [45]

It is true that rivers and streams are biodiverse ecosystems that are sensitive to change. Details about rivers and streams can be found below.

<h3>What is river and stream?</h3>

A river is a large and often winding stream which drains a land mass, carrying water down from higher areas to a lower point, oftentimes ending in another body of water, such as an ocean or in an inland sea.

On the other hand, a stream is a small river or a body of moving water confined by banks.

Rivers and streams are both freshwater ecosystems, hence, tend to respond to changes in their environment caused by anthropogenic activities.

Therefore, it is true that rivers and streams are biodiverse ecosystems that are sensitive to change.

Learn more about rivers and streams at: brainly.com/question/10904801

#SPJ4

6 0
2 years ago
Benign tumor of the adrenal medulla that causes the gland to produce excess epinephrine is called
Yuki888 [10]

Answer:

A pheochromocytoma is a tumor in the adrenal gland. It causes the gland to make too much of the hormones epinephrine and norepinephrine.

Explanation:

7 0
3 years ago
Which two phenomena are evidence that gravitational forces are attractive? Select two statements.
Vinvika [58]

Answer:

A. the rise and fall of the tides.

C. a dropped object always falls toward Earth.

Explanation:

Gravity is considered to be a universal force of attraction which acts between all objects that has both mass, energy and occupy space. Therefore, it acts in such a way as to bring objects together.

Additionally, the gravity of earth makes it possible for all physical objects to possess weight.

The two phenomena which are evidence that gravitational forces are attractive includes;

I. The rise and fall of the tides: this is caused as a result of the gravitational force of attraction exerted by the moon on earth.

II. A dropped object always falls toward Earth: this acceleration is due to the gravitational force of attraction between the Earth and the object.

7 0
3 years ago
When a plant opens and closes its stomata, it is maintaining____.?
zhannawk [14.2K]
It is maintaining homeostasis
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3 0
3 years ago
What is shown on the graph a) exponential decay of a population
Elodia [21]
Yes. What you said, bro

8 0
3 years ago
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