Answer: Option B
Explanation: The first line of defense acts a barrier and does not allows the foreign materials to enter inside the body. It includes chemical and physical barriers that are always ready to protect the body from infection.
Example: Skin and mucous membrane.
Skin is largest organ and it acts as a barrier between pathogens and human body. It acts a waterproof material and the pathogens cannot get inside through skin unless the skin is broken.
Mucous membranes also acts as first line of defense and breaks the cell wall of many bacteria entering through the openings of the body.
So, skin and mucous membrane are the first line of defense.
B - FRONTS occur when two AIR MASSES meet!
Answer:
1= EeAA
2= EEaA
3=EEaa
4=eeAA
5=eeaa
you have to put the first letter you have in the left column and then the top one
Each one is made of one original strand and one new strand.<span>It bonds together the nucleotides in the new strand</span>
Answer:
Cube with length 4cm.
Explanation:
The surface area of cube is 6a^2.
For cube with length 3
A= 6a^2
A= 6 ×(3×3)
=6(9)
= 54cm
For cube b.
A=6(a^2)
= 6×(4×4)
6(16)
= 96cm
