Answer:
Cuticle
Explanation:
Plant cuticle is a waxy covering over the aerial epidermal cells of all the plants. Waxes are composed of cutin and a various organic solvent-soluble lipids. The cuticle is an extracellular hydrophobic layer which provides protection against desiccation and external environmental stresses. In other words the cucticle helps to retain water and give plants an adavanthe to live terrestrial life.
Answer:
endocytosis is the leucocytes, neutrophils, and monocytes can engulf foreign substances like bacteria.
Explanation:
The entry of the sperm nucleus is facilitated by C) acrosome reaction. The acrosome is the head-like structure at the front of the sperm cell. This contains digestive enzymes that break down the outer membrane of the egg cell, allowing the nucleus of the sperm cell to enter and fuse with the nucleus of the egg cell.
The number of protons must differ between the atoms of 2 different elements, basically the atomic number, the numbers for which the periodic table is organized as.
Cell membranes are semi-permeable. That is why they can allow only some substances to enter the cell. It basically depends on the size of the molecules. Smaller atoms like water can easily pass through. However, macromolecules such as sugars, oils and proteins cannot easily pass because they contain a long chain of monomers.