Answer:
A steel frame used to make a bike.
The answer should be allele(s).
Alleles are alternative forms of genes. For example in eye color, there is brown eye allele that produces brown eyes or blue eye alleles that produces blue eyes.
However, note that there may be dominant or recessive alleles. Dominant alleles are always expressed, meanwhile, recessive allele is only expressed when there is no dominant allele existing.
An example is let say brown eye allele is dominant and blue eye allele is recessive. The eye gene is controlled by 2 alleles. If I had one brown eye allele and 1 blue, my eyes will be brown, because brown eye allele is dominant.
<h2>Mesophyll cells</h2>
Explanation:
The most distinctive characteristic of leaf mesophyll cells is that they are filled with many chloroplasts
Mesophyll cells constitute the main body of a leaf, occurring between upper and lower epidermis
Typically, the leaves of temperate-zone plants have two layers of mesophyll cells, the palisade mesophyll on the upper side and the spongy mesophyll on the lower side
The palisade mesophyll is a layer of densely packed, columnar cells which contain many chloroplasts, this layer is responsible for most of the photosynthesis of leaves
The spongy mesophyll is composed of large, often odd-shaped, photosynthetic cells separated from one another by large, intercellular spaces, these intercellular spaces apparently facilitate the exchange of photosynthetic gases
Answer: A semi-permeable membrane is that which only allows certain
substances to pass through.