Question

Different strains of coronavires
$different strains of coronavires$
​

Answer 1

Answer:

Recall the definition of a variable presented in Section 1.6.

Definition: Variable

A variable is a symbol (usually a letter) that stands for a value that may vary.

Let’s add the definition of a mathematical expression.

Definition: Mathematical Expression

When we combine numbers and variables in a valid way, using operations such as addition, subtraction, multiplication, division, exponentiation, and other operations and functions as yet unlearned, the resulting combination of mathematical symbols is called a mathematical expression.

Thus,

2a, x

Explanation:

Answer 2

Answer:

How Many Coronaviruses Are There?

Coronaviruses didn’t just pop up recently. They’re a large family of viruses that have been around for a long time. Many of them can cause a variety of illnesses, from a mild cough to severe respiratory illnesses.

The new (or “novel”) coronavirus is one of several known to infect humans. It’s probably been around for some time in animals. Sometimes, a virus in animals crosses over into people. That’s what scientists think happened here. So this virus isn’t new to the world, but it is new to humans. When scientists found out that it was making people sick in 2019, they named it as a novel coronavirus.

Human Coronavirus Types

Scientists have divided coronaviruses into four sub-groupings, called alpha, beta, gamma, and delta. Seven of these viruses can infect people:

229E (alpha)

NL63 (alpha)

OC43 (beta)

HKU1 (beta

MERS-CoV, a beta virus that causes Middle East respiratory syndrome (MERS)

SARS-CoV, a beta virus that causes severe acute respiratory syndrome (SARS)

SARS-CoV-2, which causes COVID-19